Method for reporting channel state information user equipment, and base station

ABSTRACT

Embodiments of the present disclosure disclose a method for reporting channel state information, including receiving a sounding signal set sent by the base station and determining a reference signal resource configuration index according to the sounding signal set, where the reference signal resource configuration index is used to indicate a reference signal resource configuration in reference signal resource configuration set information. The method also includes receiving a reference signal set sent by the base station, where the reference signal set corresponds to the reference signal resource configuration and determining channel state information according to the reference signal set. Additionally, the method includes sending the reference signal resource configuration index and the channel state information to the base station.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/CN2014/075089, filed on Apr. 10, 2014, the disclosure of which ishereby incorporated by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to the wireless communications field, andin particular, to a method for reporting channel state information, userequipment, and a base station.

BACKGROUND

Channel state information (CSI) is very important in a moderncommunications system, and can provide important information forresource scheduling, user transmission format determining, multi-userpairing, and even coordination between multiple cells. In a Long TermEvolution (LTE) system in the 3rd Generation Partnership Project (3GPP),CSI generally includes information such as a channel quality indicator(CQI), a precoding matrix indicator (PMI), and a rank indicator (RI).For a downlink (that is, a base station transmits data to userequipment) system, the user equipment may generally determine CSIaccording to a reference signal (RS, also referred to as a pilot) sentby the base station, and fed back the CSI to the base station.

Each reference signal generally corresponds to one antenna port. An LTER8 system can support a configuration of a maximum of four antenna portsby using a cell-specific reference signal (CRS); LTE R10-R11 systems cansupport a configuration of a maximum of eight antenna ports by using achannel state information reference signal (CSI RS), where “LTE Rx”denotes “LTE of an x^(th) release”.

To further improve a system capacity and system coverage, aconfiguration of more antenna ports is currently considered to beintroduced. For example, an antenna configuration of 16, 32, 64, or moreantenna ports may be introduced in an active antenna system (AAS) andMassive multiple-input multiple-output (MIMO). On the one hand, eachantenna port generally corresponds to one reference signal, and eachreference signal needs to occupy a time-frequency resource; therefore, aconfiguration of more antennas means more resource overheads. On theother hand, more antenna ports mean more corresponding channelmeasurement that needs to be performed by the user equipment and highercomplexity of CSI measurement. Therefore, avoiding excessive resourceoverheads and excessively high complexity of CSI measurement performedby the user equipment while giving full play to a multi-antennaconfiguration is now an important problem that is urgent to be resolved.

SUMMARY

Embodiments of the present disclosure provide a method for reportingchannel state information, user equipment, and a base station, which caneffectively save time-frequency resource overheads, and effectivelyreduce complexity of channel state information (CSI) measurementperformed by the user equipment or improve CSI feedback precision.

A first aspect of an embodiment of the present disclosure provides userequipment includes a sounding signal set receiving module, configured toreceive a sounding signal set sent by a base station, where the soundingsignal set includes at least one sounding signal and a resourceconfiguration index determining module, configured to determine areference signal resource configuration index according to the soundingsignal set, where the reference signal resource configuration index isused to indicate a reference signal resource configuration in referencesignal resource configuration set information. The user equipment alsoincludes a reference signal set receiving module, configured to receivea reference signal set sent by the base station, where the referencesignal set corresponds to the reference signal resource configurationindicated by the reference signal resource configuration index andchannel state information determining module, configured to determinechannel state information according to the reference signal set.Additionally, the user equipment includes a channel state informationsending module, configured to send the reference signal resourceconfiguration index and the channel state information to the basestation.

In a first possible implementation manner of the first aspect, the userequipment further includes a resource configuration set receivingmodule, configured to receive the reference signal resourceconfiguration set information sent by the base station, where thereference signal resource configuration set information includes atleast two reference signal resource configurations.

With reference to the first aspect and the first possible implementationmanner of the first aspect, in a second possible implementation mannerof the first aspect, a correspondence between the reference signalresource configuration index and the indicated reference signal resourceconfiguration is predefined or is notified by the base station by usinghigher layer signaling or downlink control information (DCI).

With reference to the first aspect and the first or second possibleimplementation manner of the first aspect, in a third possibleimplementation manner of the first aspect, the sounding signal is acell-specific reference signal (CRS) or a channel state informationreference signal CSI RS, and the reference signal resource configurationindex includes a first rank indicator (RI₁) and/or a first precodingmatrix indicator (PMI₁).

With reference to the third possible implementation manner of the firstaspect, in a fourth possible implementation manner of the first aspect,the CRS or the channel state information reference signal (CSI RS) isspecified by a specific reference signal resource configuration in thereference signal resource configuration set information.

With reference to the first aspect and the first or second possibleimplementation manner of the first aspect, in a fifth possibleimplementation manner of the first aspect, the sounding signal is asynchronization signal; and the reference signal resource configurationindex is a resource identifier carried in the synchronization signal orassociated with a resource location of the synchronization signal, wherethe resource identifier carried in the synchronization signal orassociated with the resource location of the synchronization signalindicates a reference signal resource configuration in the referencesignal resource configuration set information.

With reference to the fifth possible implementation manner of the firstaspect, in a sixth possible implementation manner of the first aspect, adifferent resource identifier carried in the synchronization signal isdenoted by a different synchronization signal sequence.

With reference to the first aspect and the first or second possibleimplementation manner of the first aspect, in a seventh possibleimplementation manner of the first aspect, the sounding signal is abroadcast channel; and the reference signal resource configuration indexis a resource identifier carried in the broadcast channel or associatedwith a resource location of the broadcast channel, where the resourceidentifier carried in the broadcast channel or associated with theresource location of the broadcast channel indicates a reference signalresource configuration in the reference signal resource configurationset information.

With reference to the seventh possible implementation manner of thefirst aspect, in an eighth possible implementation manner of the firstaspect, a different resource identifier carried in the broadcast channelis denoted by a different cyclic redundancy check mask.

With reference to the first aspect and any one of the first to eighthpossible implementation manners of the first aspect, in a ninth possibleimplementation manner of the first aspect, the channel state informationdetermining module is configured to determine a second precoding matrixindicator (PMI₂) according to the reference signal set, where the PMI₂corresponds to a precoding matrix selected from a codebook, and thecodebook is determined according to the reference signal resourceconfiguration index; and the channel state information includes thePMI₂.

With reference to the first aspect and any one of the first to ninthpossible implementation manners of the first aspect, in a tenth possibleimplementation manner of the first aspect, the channel state informationsending module is configured to: send the reference signal resourceconfiguration index and the channel state information to the basestation separately on a same subframe or on different subframes.

With reference to the tenth possible implementation manner of the firstaspect, in an eleventh possible implementation manner of the firstaspect, a period of sending the reference signal resource configurationindex by the channel state information sending module is longer than aperiod of sending the channel state information.

With reference to the first aspect and any one of the first to eleventhpossible implementation manners of the first aspect, in a twelfthpossible implementation manner of the first aspect, the reference signalresource configuration includes antenna port information and referencesignal configuration information and/or reference signal sequenceinformation, where the reference signal configuration information isused to indicate a resource element used for sending a reference signalon an antenna port.

With reference to the twelfth possible implementation manner of thefirst aspect, in a thirteenth possible implementation manner of thefirst aspect, the reference signal sequence information is an initialvalue or cyclic shift information of a reference signal sequence.

With reference to the twelfth or thirteenth possible implementationmanner of the first aspect, in a fourteenth possible implementationmanner of the first aspect, antenna port sets corresponding to the tworeference signal resource configurations have at least one same antennaport.

With reference to the first aspect and the first to fourteenth possibleimplementation manners of the first aspect, in a fifteenth possibleimplementation manner of the first aspect, a different antenna portcorresponding to each reference signal resource configuration includedin the reference signal resource configuration set information uses adifferent resource reference signal configuration or a differentreference signal sequence.

A second aspect of an embodiment of the present disclosure provides abase station, including a sounding signal set sending module, configuredto send a sounding signal set to user equipment, where the soundingsignal set includes at least one sounding signal, so that the userequipment determines a reference signal resource configuration indexaccording to the sounding signal set, where the reference signalresource configuration index is used to indicate a reference signalresource configuration in reference signal resource configuration setinformation. The base station also includes a reference signal setsending module, configured to send at least two reference signal sets tothe user equipment, where the at least two reference signal setscorrespond to at least two reference signal resource configurationsincluded in the reference signal resource configuration set information.Additionally, the base station includes a channel state informationreceiving module, configured to receive the reference signal resourceconfiguration index and channel state information that are sent by theuser equipment, where the channel state information is obtained by theuser equipment according to a reference signal resource configurationindicated by the reference signal resource configuration index.

In a first possible implementation manner of the second aspect, the basestation further includes: a resource configuration set sending module,configured to send the reference signal resource configuration setinformation to the user equipment, where the reference signal resourceconfiguration set information includes the at least two reference signalresource configurations.

With reference to the second aspect and the first possibleimplementation manner of the second aspect, in a second possibleimplementation manner of the second aspect, a correspondence between thereference signal resource configuration index and the indicatedreference signal resource configuration is predefined or is notified tothe user equipment by using higher layer signaling or DCI.

With reference to the second aspect and the first or second possibleimplementation manner of the second aspect, in a third possibleimplementation manner of the second aspect, the sounding signal is a CRSor a CSI RS; and the reference signal resource configuration indexincludes an RI₁ and/or a PMI₁.

With reference to the third possible implementation manner of the secondaspect, in a fourth possible implementation manner of the second aspect,the CRS or the CSI RS is specified by a specific reference signalresource configuration in the reference signal resource configurationset information.

With reference to the second aspect and the first or second possibleimplementation manner of the second aspect, in a fifth possibleimplementation manner of the second aspect, the sounding signal is asynchronization signal; and the reference signal resource configurationindex is a resource identifier carried in the synchronization signal orassociated with a resource location of the synchronization signal, wherethe resource identifier carried in the synchronization signal orassociated with the resource location of the synchronization signalindicates a reference signal resource configuration in the referencesignal resource configuration set information.

With reference to the fifth possible implementation manner of the secondaspect, in a sixth possible implementation manner of the second aspect,a different resource identifier carried in the synchronization signal isdenoted by a different synchronization signal sequence.

With reference to the second aspect and the first or second possibleimplementation manner of the second aspect, in a seventh possibleimplementation manner of the second aspect, the sounding signal is abroadcast channel; and the reference signal resource configuration indexis a resource identifier carried in the broadcast channel or associatedwith a resource location of the broadcast channel, where the resourceidentifier carried in the broadcast channel or associated with theresource location of the broadcast channel indicates a reference signalresource configuration in the reference signal resource configurationset information.

With reference to the seventh possible implementation manner of thesecond aspect, in an eighth possible implementation manner of the secondaspect, a different resource identifier carried in the broadcast channelis denoted by a different cyclic redundancy check mask.

With reference to the second aspect and any one of the first to eighthpossible implementation manners of the second aspect, in a ninthpossible implementation manner of the second aspect, the channel stateinformation includes a PMI₂, and the PMI₂ is determined by the userequipment according to the reference signal set, and the PMI₂corresponds to a precoding matrix selected by the user equipment from acodebook.

With reference to the second aspect and any one of the first to ninthpossible implementation manners of the second aspect, in a tenthpossible implementation manner of the second aspect, the channel stateinformation receiving module is configured to: receive, on a samesubframe or on different subframes, the reference signal resourceconfiguration index and the channel state information separately thatare sent by the user equipment.

With reference to the tenth possible implementation manner of the secondaspect, in an eleventh possible implementation manner of the secondaspect, a period of receiving, by the channel state informationreceiving module, the reference signal resource configuration index sentby the user equipment, is longer than a period of receiving the channelstate information.

With reference to the second aspect and any one of the first to eleventhpossible implementation manners of the second aspect, in a twelfthpossible implementation manner of the second aspect, the referencesignal resource configuration includes antenna port information andreference signal configuration information and/or reference signalsequence information, where the reference signal configurationinformation is used to indicate a resource element used for sending areference signal on an antenna port.

With reference to the twelfth possible implementation manner of thesecond aspect, in a thirteenth possible implementation manner of thesecond aspect, the reference signal sequence information is an initialvalue or cyclic shift information of a reference signal sequence.

With reference to the twelfth or thirteenth possible implementationmanner of the second aspect, in a fourteenth possible implementationmanner of the second aspect, antenna port sets corresponding to the tworeference signal resource configurations have at least one same antennaport.

With reference to the second aspect and the first to fourteenth possibleimplementation manners of the second aspect, in a fifteenth possibleimplementation manner of the second aspect, a different antenna portcorresponding to each reference signal resource configuration includedin the reference signal resource configuration set information uses adifferent resource reference signal configuration or a differentreference signal sequence.

A third aspect of an embodiment of the present disclosure provides amethod for reporting channel state information, including: receiving, byuser equipment, a sounding signal set sent by a base station, where thesounding signal set includes at least one sounding signal; determining,by the user equipment, a reference signal resource configuration indexaccording to the sounding signal set, where the reference signalresource configuration index is used to indicate a reference signalresource configuration in reference signal resource configuration setinformation; receiving, by the user equipment, a reference signal setsent by the base station, where the reference signal set corresponds tothe reference signal resource configuration indicated by the referencesignal resource configuration index; determining, by the user equipment,channel state information according to the reference signal set; andsending, by the user equipment, the reference signal resourceconfiguration index and the channel state information to the basestation.

In a first possible implementation manner of the third aspect, themethod further includes: receiving, by the user equipment, the referencesignal resource configuration set information sent by the base station,where the reference signal resource configuration set informationincludes at least two reference signal resource configurations.

With reference to the third aspect and the first possible implementationmanner of the third aspect, in a second possible implementation mannerof the third aspect, a correspondence between the reference signalresource configuration index and the indicated reference signal resourceconfiguration is predefined or is notified by the base station by usinghigher layer signaling or DCI.

With reference to the third aspect and the first or second possibleimplementation manner of the third aspect, in a third possibleimplementation manner of the third aspect, the sounding signal is a CRSor a channel state information reference signal CSI RS; and thereference signal resource configuration index includes an RI₁ and/or aPMI₁.

With reference to the third possible implementation manner of the thirdaspect, in a fourth possible implementation manner of the third aspect,the CRS or the CSI RS is specified by a specific reference signalresource configuration in the reference signal resource configurationset information.

With reference to the third aspect and the first or second possibleimplementation manner of the third aspect, in a fifth possibleimplementation manner of the third aspect, the sounding signal is asynchronization signal; and the reference signal resource configurationindex is a resource identifier carried in the synchronization signal orassociated with a resource location of the synchronization signal, wherethe resource identifier carried in the synchronization signal orassociated with the resource location of the synchronization signalindicates a reference signal resource configuration in the referencesignal resource configuration set information.

With reference to the fifth possible implementation manner of the thirdaspect, in a sixth possible implementation manner of the third aspect, adifferent resource identifier carried in the synchronization signal isdenoted by a different synchronization signal sequence.

With reference to the third aspect and the first or second possibleimplementation manner of the third aspect, in a seventh possibleimplementation manner of the third aspect, the sounding signal is abroadcast channel; and the reference signal resource configuration indexis a resource identifier carried in the broadcast channel or associatedwith a resource location of the broadcast channel, where the resourceidentifier carried in the broadcast channel or associated with theresource location of the broadcast channel indicates a reference signalresource configuration in the reference signal resource configurationset information.

With reference to the seventh possible implementation manner of thethird aspect, in an eighth possible implementation manner of the thirdaspect, a different resource identifier carried in the broadcast channelis denoted by a different cyclic redundancy check mask.

With reference to the third aspect and any one of the first to eighthpossible implementation manners of the third aspect, in a ninth possibleimplementation manner of the third aspect, the determining channel stateinformation according to the reference signal set includes: determining,by the user equipment, a PMI₂ according to the reference signal set,where the PMI₂ corresponds to a precoding matrix selected from acodebook, and the codebook is determined according to the referencesignal resource configuration index; and the channel state informationincludes the PMI₂.

With reference to the third aspect and any one of the first to ninthpossible implementation manners of the third aspect, in a tenth possibleimplementation manner of the third aspect, the sending the referencesignal resource configuration index and the channel state information tothe base station includes: sending, by the user equipment, the referencesignal resource configuration index and the channel state information tothe base station separately on a same subframe or on differentsubframes.

With reference to the tenth possible implementation manner of the thirdaspect, in an eleventh possible implementation manner of the thirdaspect, a period of sending the reference signal resource configurationindex is longer than a period of sending the channel state information.

With reference to the third aspect and any one of the first to eleventhpossible implementation manners of the third aspect, in a twelfthpossible implementation manner of the third aspect, the reference signalresource configuration includes antenna port information and referencesignal configuration information and/or reference signal sequenceinformation, where the reference signal configuration information isused to indicate a resource element used for sending a reference signalon an antenna port.

With reference to the twelfth possible implementation manner of thethird aspect, in a thirteenth possible implementation manner of thethird aspect, the reference signal sequence information is an initialvalue or cyclic shift information of a reference signal sequence.

With reference to the twelfth or thirteenth possible implementationmanner of the third aspect, in a fourteenth possible implementationmanner of the third aspect, antenna port sets corresponding to the tworeference signal resource configurations have at least one same antennaport.

With reference to the third aspect and the first to fourteenth possibleimplementation manners of the third aspect, in a fifteenth possibleimplementation manner of the third aspect, a different antenna portcorresponding to each reference signal resource configuration includedin the reference signal resource configuration set information uses adifferent resource reference signal configuration or a differentreference signal sequence.

A fourth aspect of an embodiment of the present disclosure provides amethod for reporting channel state information, including: sending, by abase station, a sounding signal set to user equipment, where thesounding signal set includes at least one sounding signal, so that theuser equipment determines a reference signal resource configurationindex according to the sounding signal set, where the reference signalresource configuration index is used to indicate a reference signalresource configuration in reference signal resource configuration setinformation; sending, by the base station, at least two reference signalsets to the user equipment, where the at least two reference signal setscorrespond to at least two reference signal resource configurationsincluded in the reference signal resource configuration set information;and receiving, by the base station, the reference signal resourceconfiguration index and channel state information that are sent by theuser equipment, where the channel state information is obtained by theuser equipment according to a reference signal resource configurationindicated by the reference signal resource configuration index.

In a first possible implementation manner of the fourth aspect, themethod further includes: sending, by the base station, the referencesignal resource configuration set information to the user equipment,where the reference signal resource configuration set informationincludes the at least two reference signal resource configurations.

With reference to the fourth aspect and the first or second possibleimplementation manner of the fourth aspect, in a third possibleimplementation manner of the fourth aspect, the sounding signal is a CRSor a channel state information reference signal CSI RS; and thereference signal resource configuration index includes an RI₁ and/or aPMI₁.

With reference to the third possible implementation manner of the fourthaspect, in a fourth possible implementation manner of the fourth aspect,the CRS or the CSI RS is specified by a specific reference signalresource configuration in the reference signal resource configurationset information.

With reference to the fourth aspect and the first or second possibleimplementation manner of the fourth aspect, in a fifth possibleimplementation manner of the fourth aspect, the sounding signal is asynchronization signal; and the reference signal resource configurationindex is a resource identifier carried in the synchronization signal orassociated with a resource location of the synchronization signal, wherethe resource identifier carried in the synchronization signal orassociated with the resource location of the synchronization signalindicates a reference signal resource configuration in the referencesignal resource configuration set information.

With reference to the fifth possible implementation manner of the fourthaspect, in a sixth possible implementation manner of the fourth aspect,a different resource identifier carried in the synchronization signal isdenoted by a different synchronization signal sequence.

With reference to the fourth aspect and the first or second possibleimplementation manner of the fourth aspect, in a seventh possibleimplementation manner of the fourth aspect, the sounding signal is abroadcast channel; and the reference signal resource configuration indexis a resource identifier carried in the broadcast channel or associatedwith a resource location of the broadcast channel, where the resourceidentifier carried in the broadcast channel or associated with theresource location of the broadcast channel indicates a reference signalresource configuration in the reference signal resource configurationset information.

With reference to the seventh possible implementation manner of thefourth aspect, in an eighth possible implementation manner of the fourthaspect, a different resource identifier carried in the broadcast channelis denoted by a different cyclic redundancy check mask.

With reference to the fourth aspect and any one of the first to eighthpossible implementation manners of the fourth aspect, in a ninthpossible implementation manner of the fourth aspect, the channel stateinformation includes a PMI₂, and the PMI₂ is determined by the userequipment according to the reference signal set, and the PMI₂corresponds to a precoding matrix selected by the user equipment from acodebook.

With reference to the fourth aspect and any one of the first to ninthpossible implementation manners of the fourth aspect, in a tenthpossible implementation manner of the fourth aspect, the receiving thereference signal resource configuration index and channel stateinformation that are sent by the user equipment includes: receiving, bythe base station on a same subframe or on different subframes, thereference signal resource configuration index and the channel stateinformation separately that are sent by the user equipment.

With reference to the tenth possible implementation manner of the fourthaspect, in an eleventh possible implementation manner of the fourthaspect, a period of receiving the reference signal resourceconfiguration index sent by the user equipment is longer than a periodof receiving the channel state information.

With reference to the fourth aspect and any one of the first to eleventhpossible implementation manners of the second aspect, in a twelfthpossible implementation manner of the second aspect, the referencesignal resource configuration includes antenna port information andreference signal configuration information and/or reference signalsequence information, where the reference signal configurationinformation is used to indicate a resource element used for sending areference signal on an antenna port.

With reference to the twelfth possible implementation manner of thefourth aspect, in a thirteenth possible implementation manner of thefourth aspect, the reference signal sequence information is an initialvalue or cyclic shift information of a reference signal sequence.

With reference to the twelfth or thirteenth possible implementationmanner of the fourth aspect, in a fourteenth possible implementationmanner of the fourth aspect, antenna port sets corresponding to the tworeference signal resource configurations have at least one same antennaport.

With reference to the fourth aspect and the first to fourteenth possibleimplementation manners of the fourth aspect, in a fifteenth possibleimplementation manner of the fourth aspect, a different antenna portcorresponding to each reference signal resource configuration includedin the reference signal resource configuration set information uses adifferent resource reference signal configuration or a differentreference signal sequence.

A fifth aspect of an embodiment of the present disclosure provides acommunications system, including the user equipment provided in thefirst aspect and the base station provided in the second aspect, wherethe user equipment is configured to: receive a sounding signal set sentby the base station, where the sounding signal set includes at least onesounding signal; determine a reference signal resource configurationindex according to the sounding signal set, where the reference signalresource configuration index is used to indicate a reference signalresource configuration in reference signal resource configuration setinformation; receive a reference signal set sent by the base station,where the reference signal set corresponds to the reference signalresource configuration indicated by the reference signal resourceconfiguration index; determine channel state information according tothe reference signal set; and send the reference signal resourceconfiguration index and the channel state information to the basestation; and the base station is configured to: send a sounding signalset to the user equipment, where the sounding signal set includes atleast one sounding signal, so that the user equipment determines areference signal resource configuration index according to the soundingsignal set, where the reference signal resource configuration index isused to indicate a reference signal resource configuration in referencesignal resource configuration set information; send at least tworeference signal sets to the user equipment, where the at least tworeference signal sets correspond to at least two reference signalresource configurations included in the reference signal resourceconfiguration set information; and receive the reference signal resourceconfiguration index and channel state information that are sent by theuser equipment, where the channel state information is obtained by theuser equipment according to a reference signal resource configurationindicated by the reference signal resource configuration index.

It can be learned from the foregoing description that, in theembodiments of the present disclosure, a base station sends a soundingsignal set to user equipment, and the user equipment determines alocally appropriate reference signal resource configuration indexaccording to the sounding signal set, where the reference signalresource configuration index is used to indicate a reference signalresource configuration in reference signal resource configuration setinformation. When the base station sends a reference signal set to theoutside, the user equipment obtains only a reference signal setcorresponding to the reference signal resource configuration indicatedby the reference signal resource configuration index, and thendetermines channel state information according to the reference signalset and reports the channel state information to the base station. Thiscan effectively save time-frequency resource overheads, and effectivelyreduce complexity of CSI measurement performed by the user equipment orimprove CSI feedback precision.

BRIEF DESCRIPTION OF THE DRAWINGS

To describe the technical solutions in the embodiments of the presentdisclosure more clearly, the following briefly describes theaccompanying drawings required for describing the embodiments.Apparently, the accompanying drawings in the following description showmerely some embodiments of the present disclosure, and a person ofordinary skill in the art may still derive other drawings from theseaccompanying drawings without creative efforts.

FIG. 1a is a schematic diagram of a frame structure according to anembodiment of the present disclosure;

FIG. 1b is a schematic diagram of another frame structure according toan embodiment of the present disclosure;

FIG. 1c is a schematic structural diagram of a resource grid accordingto an embodiment of the present disclosure;

FIG. 1d is a schematic diagram of a directive gain of a beam accordingto an embodiment of the present disclosure;

FIG. 2a is a schematic diagram of a reference signal configuration with8 antenna ports according to an embodiment of the present disclosure;

FIG. 2b is a schematic diagram of another reference signal configurationwith 8 antenna ports according to an embodiment of the presentdisclosure;

FIG. 3a is a schematic diagram of a reference signal configuration with16 antenna ports according to an embodiment of the present disclosure;

FIG. 3b is a schematic diagram of another reference signal configurationwith 16 antenna ports according to an embodiment of the presentdisclosure;

FIG. 4 is a schematic structural diagram of user equipment according toan embodiment of the present disclosure;

FIG. 5 is a schematic structural diagram of a base station according toan embodiment of the present disclosure;

FIG. 6 is a schematic structural diagram of another user equipmentaccording to an embodiment of the present disclosure;

FIG. 7 is a schematic structural diagram of another base stationaccording to an embodiment of the present disclosure;

FIG. 8 is a schematic flowchart of a method for reporting channel stateinformation according to an embodiment of the present disclosure; and

FIG. 9 is a schematic flowchart of another method for reporting channelstate information according to an embodiment of the present disclosure.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The following clearly describes the technical solutions in theembodiments of the present disclosure with reference to the accompanyingdrawings in the embodiments of the present disclosure. Apparently, thedescribed embodiments are merely some but not all of the embodiments ofthe present disclosure. All other embodiments obtained by a person ofordinary skill in the art based on the embodiments of the presentdisclosure without creative efforts shall fall within the protectionscope of the present disclosure.

It should be understood that, the technical solutions of the embodimentsof the present disclosure may be applied to various communicationssystems such as a Global System for Mobile Communications (GSM), a CodeDivision Multiple Access (CDMA) system, a Wideband Code DivisionMultiple Access (WCDMA) system, a general packet radio service (GPRS), aLong Term Evolution (LTE) system, an LTE frequency division duplex (FDD)system, LTE time division duplex (TDD) system, a Universal MobileTelecommunications System (UMTS), or a Worldwide Interoperability forMicrowave Access (WiMAX) communications system.

It should also be understood that in the embodiments of the presentdisclosure, user equipment (UE) may be referred to as a terminal, amobile station (MS), a mobile terminal, or the like. The user equipmentmay communicate with one or more core networks by using a radio accessnetwork (RAN). For example, the user equipment may be a mobile phone(also referred to as a “cellular” phone) or a computer with a mobileterminal. For example, the user equipment may also be a portable,pocket-sized, handheld, computer built-in, or in-vehicle mobileapparatus, which exchanges voice and/or data with the radio accessnetwork.

In the embodiments of the present disclosure, a base station may be abase transceiver station (BTS) in the GSM or CDMA, or may be a nodeB(NB) in the WCDMA, or may be an evolved NodeB (eNB) in the LTE, which isnot limited in the present disclosure. However, for ease of description,the following embodiments are described by using an eNB as an example.

For ease of understanding, an LTE system is used as an example todescribe a frame structure, a timeslot structure, and a resource gridstructure first. In the LTE system, uplink and downlink transmission isorganized into a radio frame. Each radio frame is 10 milliseconds long,and each radio frame includes 10 1-millisecond subframes or includes 200.5-millisecond timeslots (slot) numbered from 0 to 19. One subframe isdefined as two consecutive timeslots. There are two frame structures,type 1 and type 2, which are respectively applied to an FDD system and aTDD system. Frame structure type 1 (FS1) and frame structure type 2(FS2) are shown in FIG. 1a and FIG. 1b respectively. In addition, inFIG. 1b , half-frame denotes a half radio frame, DwPTS denotes adownlink pilot timeslot, UpPTS denotes an uplink pilot timeslot, and Gpdenotes a guard interval between the uplink pilot timeslot and thedownlink pilot timeslot.

One subframe is defined as two consecutive timeslots. A signaltransmitted in each timeslot may be denoted by one or more resourcegrids. As shown in FIG. 1c , a resource block denotes a resource grid(RB). Using a downlink system as an example, N_(RB) ^(DL)N_(sc) ^(RB)consecutive subcarriers and N_(symb) ^(DL) consecutive OFDM symbols forma resource grid structure, where N_(RB) ^(DL)N_(sc) ^(RB) and N_(symb)^(DL) are respectively a frequency-domain metric identifier and atime-domain metric identifier in an LTE physical layer protocol, N_(RB)^(DL) is a system bandwidth expressed in units of resource blocks RBs,N_(sc) ^(RB) is a quantity of subcarriers in an RB, and N_(symb) ^(DL)is a quantity of OFDM symbols in a downlink timeslot. Each element in aresource grid is referred to as a resource element (RE), and each RE maybe uniquely identified by an index pair (k,l) in a timeslot, where k=0,. . . , N_(sc) ^(RB)−1 is a frequency domain index in the timeslot, andl=0, . . . , N_(symb) ^(DL)−1 is a time domain index in the timeslot.N_(symb) ^(DL) consecutive OFDM symbols in the time domain and N_(sc)^(RB) consecutive subcarriers in the frequency domain are defined as aresource block (RB).

In addition, an antenna port is defined by the LTE system so that achannel over which a symbol on the antenna port is sent can be inferredfrom a channel over which another symbol on the same antenna port issent. Each antenna port has a resource grid. Actually, each antenna portmay correspond to one physical antenna, or correspond to one virtualantenna, that is, a combination of multiple physical antennas. Eachantenna port may have a same or different antenna directivity pattern.For example, antenna ports of different beam directivities or beamwidths are obtained by changing a horizontal tilt angle or vertical tiltangle of a different antenna array or by means of weighting or phaseshifting of a different combination of multiple physical antennas. Asshown in FIG. 1d , B0 and B1 are directivity patterns of two antennaports of different beam directivities, where angle denotes a tilt angleof a beam directivity (unit: dB), and Gain Pattern denotes a gain (unit:deg).

It should be pointed out that the present disclosure is not limited tothe foregoing composition of a frame structure, a timeslot structure,and a physical resource element. For example, in a future high-frequencysystem, a frame structure may include more timeslots or OFDM symbols, orthe subcarrier spacing is wider. For example, one radio frame structuremay include 40 or 80 timeslots, or the subcarrier spacing is 60 kHz.

FIG. 4 is a schematic structural diagram of user equipment according toan embodiment of the present disclosure. As shown in the figure, theuser equipment in this embodiment of the present disclosure may includeat least a sounding signal set receiving module no, a resourceconfiguration index determining module 120, a reference signal setreceiving module 130, a channel state information determining module140, and a channel state information sending module 150.

The sounding signal set receiving module no is configured to receive asounding signal set sent by the base station, where the sounding signalset includes at least one sounding signal.

Specifically, the sounding signal set receiving module no receives thesounding signal set sent by the base station, where the sounding signalset includes at least one sounding signal. It should be pointed outthat:

In a first optional implementation manner, the sounding signal is a CRS(Cell-Specific Reference Signal) or a CSI RS (Channel State InformationReference Signal). The CRS may support a cell-specific antenna portconfiguration, and is received by all user equipments in this cell. Forexample, the CRS may be a reference signal corresponding to an antennaport 0, 1, 2, or 3 in an LTE R8 system. The CSI RS supports signaltransmission on a cell-specific antenna port and signal receiving on auser equipment specific antenna port. For example, the CSI RS may be areference signal corresponding to an antenna port 15, 16, . . . , or 22in an LTE R10 system. It should be pointed out that the CRS or the CSIRS is not limited to a current LTE system.

In a second optional implementation manner, the sounding signal is asynchronization signal. The synchronization signal is used to implementtime and frequency synchronization. One of multiple known or optionalsynchronization signal sequences is mapped to a resource element set ofa synchronization signal. According to the known or optionalsynchronization signal sequence, the user equipment may implement timeand frequency synchronization by detecting the synchronization signal.

Specifically, the synchronization signal may be sent on at least oneresource element set separately. For example, using a frame structure inan LTE system as an example, the at least one resource element set maybe:

$\begin{matrix}{S_{0}^{SS} = \left\{ {{{\left( {k,l,n_{s}} \right)❘k} = {n - \frac{N_{SS}}{2} + \frac{N_{RB}^{DL}N_{sc}^{RB}}{2}}},{n = 0},\ldots\mspace{11mu},{{N_{SS} - 1};{l = {N_{symb}^{RB} - 1}};{{n_{s}{{mod}N}_{slot}^{F}} = 0}},\frac{N_{slot}^{F}}{2}} \right\}} & (1) \\{S_{1}^{SS} = \left\{ {{{\left( {k,l,n_{s}} \right)❘k} = {n - \frac{N_{SS}}{2} + \frac{N_{RB}^{DL}N_{sc}^{RB}}{2}}},{n = 0},\ldots\mspace{11mu},{{N_{SS} - 1};{l = {N_{symb}^{RB} - 1}};{{n_{s}{{mod}N}_{slot}^{F}} = \frac{N_{slot}^{F}}{4}}},\frac{3N_{slot}^{F}}{4}} \right\}} & (2)\end{matrix}$

The triplet (k, l, n_(s)) denotes a location of a resource element usedfor the synchronization signal, where k, l, and n_(s) are respectively asubcarrier index, an OFDM symbol index, and a timeslot index of theresource element; N_(SS) denotes a length of a synchronization signalsequence.

Specifically, in each resource element set, the synchronization signalsends a synchronization signal sequence. The synchronization signalsequence may be a Zadoff-Chu (ZC) sequence. Using N_(SS)=62 as anexample, the synchronization signal sequence is the following ZCsequence:

$\begin{matrix}{{d_{u}(n)} = \left\{ \begin{matrix}e^{{- j}\;\frac{\pi\;{{un}{({n + 1})}}}{63}} & {{n = 0},1,\ldots\mspace{11mu},30} \\e^{{- j}\;\frac{\pi\;{u{({n + 1})}}{({n + 2})}}{63}} & {{n = 31},32,\ldots\mspace{11mu},61}\end{matrix} \right.} & (3)\end{matrix}$or a cyclic shift (Cyclic Shift) of the ZC sequence:d _(u,v)(n)=d _(u)((n+v)mod N _(SS)  (4)

The parameter u is a root index of the ZC sequence, and its value maybe, for example, 25, 29, or 34. The parameter v is a cyclic shift value,and its value may be, for example, a positive integer such as 3 or 6.

Optionally, the synchronization signal sequence may also be an msequence or a Gold sequence or a combination thereof, and is not furtherenumerated herein.

Specifically, the synchronization signal sequence may be separatelymapped to different resource element sets. Using the ZC sequence whoselength is 62 as an example, 62 elements in the sequence may be mapped to62 resource element locations respectively. For example, a sequenceelement in an RE location (k, l, n_(s)) in the resource element setS_(i) ^(SS) is:a _(k,l,n) _(s) =d _(u) _(i) (n),(k,l,n _(s))∈S _(i) ^(SS)  (5)ora _(k,l,n) _(s) =d _(u) _(i) _(,v) _(i) (n),(k,l,n _(s))∈S _(i) ^(SS) ,i=0, 1, . . .   (6)where u_(i) and v_(i) are respectively a root index value and a cyclicshift value of a ZC sequence used for the synchronization signal on theresource element set S_(i) ^(SS). A synchronization signal on adifferent resource element set S_(i) ^(SS) may use a different rootindex value or a different cyclic shift value or a combination thereof.It should be pointed out that a different u_(i) or v_(i) or acombination (u_(i), v_(i)) thereof may correspond to a different pieceof information, so that the synchronization signal sent on the differentresource element sets carries different information.

In a third optional implementation manner, the sounding signal is abroadcast channel. The broadcast channel is used to send a broadcastmessage. The broadcast message may include, for example, a systembandwidth, a system frame number, physical channel configurationindication information, or a combination thereof.

Specifically, the broadcast channel may be sent on at least one resourceelement set separately. For example, using a frame structure in an LTEsystem as an example, the at least one resource element set may be:

$\begin{matrix}{S_{0}^{BCH} = \left\{ {{{\left( {k,l,n_{s},n_{f}} \right)❘k} = {\frac{N_{RB}^{DL}N_{sc}^{RB}}{2} - 36 + k^{\prime}}},{k^{\prime} = 0},1,\ldots\mspace{11mu},{71;{l = 0}},1,2,{3;{n_{s} = 1}},{{n_{f}{{mod}\left( {4N} \right)}} = j}} \right\}} & (7) \\{S_{1}^{BCH} = \left\{ {{{\left( {k,l,n_{s},n_{f}} \right)❘k} = {\frac{N_{RB}^{DL}N_{sc}^{RB}}{2} - 36 + k^{\prime}}},{k^{\prime} = 0},1,\ldots\mspace{11mu},{71;{l = 4}},5,{6;{n_{s} = 1}},{{n_{f}{{mod}\left( {4N} \right)}} = j}} \right\}} & (8) \\{\mspace{79mu}{or}} & \; \\{S_{0}^{BCH} = \left\{ {{{\left( {k,l,n_{s},n_{f}} \right)❘k} = {\frac{N_{RB}^{DL}N_{sc}^{RB}}{2} - 36 + k^{\prime}}},{k^{\prime} = 0},1,\ldots\mspace{11mu},{71;{l = 0}},1,2,{3;{n_{s} = 1}},{{n_{f}{{mod}\left( {4N} \right)}} = j_{0}}} \right\}} & (9) \\{S_{1}^{BCH} = \left\{ {{{\left( {k,l,n_{s},n_{f}} \right)❘k} = {\frac{N_{RB}^{DL}N_{sc}^{RB}}{2} - 36 + k^{\prime}}},{k^{\prime} = 0},1,\ldots\mspace{11mu},{71;{l = 0}},1,2,{3;{n_{s} = 1}},{{n_{f}{{mod}\left( {4N} \right)}} = j_{1}}} \right\}} & (10)\end{matrix}$

The quadruplet (k, l, n_(s), n_(f)) denotes a location of a resourceelement used for the broadcast channel, where k, l, n_(s), and n_(f) arerespectively a subcarrier index, an OFDM symbol index, a timeslot index,and a system frame number of the resource element; j₀≠j₁, and valueranges of all parameters j, j₀, and j₁ are 0 to 4N−1. The positiveinteger N in formulas (7) to (10) may be 1 or a positive integer greaterthan 1.

Specifically, a broadcast channel sent by each resource element groupmay be mapped to a corresponding resource element set after undergoingchannel coding (for example, by using a convolutional code or a Turbocode) and modulation. In addition, before channel coding, a cyclicredundancy check (CRC) code may be appended to the broadcast message.

Optionally, the broadcast channels in the different resource elementsets may further carry additional information separately in addition tothe system broadcast information. Optionally, an implementation mannermay be:

Manner 1: The additional information and the broadcast information forma broadcast message, and undergo processing such as channel coding.

Manner 2: The additional information is denoted by a different CRC mask.Specifically, a CRC check bit corresponding to the broadcast messagecarried in the broadcast channel is p_(n), n=0, 1, 2, . . . , N_(CRC)−1,and a CRC mask corresponding to the indication information is x_(n),n=0, 1, 2, . . . , N_(CRC)−1. Therefore, after CRC mask scrambling, thefollowing bit sequence is generated:c _(k)=(p _(n) +x _(n))mod 2, n=0, 1, 2, . . . , N _(CRC)−1  (11)

For example, when N_(CRC)=16 or 24, four different CRC masks may berespectively:X ₁ ={x _(n) |x _(n)=0, n=0, . . . , N _(CRC)−1}  (12)X ₂ ={X _(n) |x _(n)=1, n=0, . . . , N _(CRC)1−1}  (13)X ₃ ={x _(n) |x _(n) =n mod 2, n=0, . . . , N _(CRC)−1}  (14)X ₄ ={x _(n) |x _(n)=(n+1)mod 2, n=0, . . . , N _(CRC)=1}  (15)

It should be specially noted that the foregoing three implementationmanners merely show three specific sounding signal types proposed inthis embodiment of the present disclosure. However, type of the soundingsignal is not limited thereto, and is not enumerated exhaustivelyherein.

The resource configuration index determining module 120 is configured todetermine a reference signal resource configuration index according tothe sounding signal set, where the reference signal resourceconfiguration index is used to indicate a reference signal resourceconfiguration in reference signal resource configuration setinformation.

Specifically, the resource configuration index determining module 120determines the reference signal resource configuration index accordingto the received sounding signal set.

It should be pointed out that the reference signal resourceconfiguration index is used to indicate a reference signal resourceconfiguration in the reference signal resource configuration setinformation. Generally, each reference signal corresponds to one antennaport. By means of a least square (LS) method, a minimum mean squarederror (MMSE) method, or the like, a channel estimation on acorresponding antenna port may be obtained according to a resourceelement location occupied by each reference signal in a resource grid ofthe corresponding antenna port.

Specifically, the reference signal resource configuration may includeinformation such as a supported quantity of antenna ports, a referencesignal sending period and an offset in the sending period, an RElocation occupied by a reference signal, or a reference signal sequence.The RE location occupied by the reference signal or a time-frequencypattern of the reference signal is generally referred to as a referencesignal configuration. Using 8 antenna ports as an example, RE locationscorresponding to the 8 antenna ports in frame structures FS1 and FS2 areshown in FIG. 2a and FIG. 2b respectively. Using 16 antenna ports as anexample, RE locations corresponding to the 16 antenna ports in the framestructures FS1 and FS are shown in FIG. 3a and FIG. 3b respectively.Using FIG. 3a as an example, RE locations denoted by digits 0, 1, . . ., 7 in the figure are locations occupied by reference signals. In FIG.2a , FIG. 2b , FIG. 3a , and FIG. 3b , PDCCH (Physical Downlink ControlChannel) is a physical downlink control channel, and may carry downlinkcontrol information; PDSCH (Physical Downlink Shared Channel) is aphysical downlink shared channel, and may carry data of a transmissionchannel; CRS port denotes a port to which the cell-specific referencesignal belongs, and DMRS (Demodulation Reference Signal) is ademodulation reference signal.

Specifically, the reference signal sends a reference signal sequence onan occupied resource element set. Optionally, the reference signalsequence may be a ZC sequence or an m sequence, or may be obtainedaccording to a combination of two base sequences or according to apseudo random sequence, or the like.

For example, the reference signal sequence may be generated according toa pseudo random sequence, for example:

$\begin{matrix}{{{r_{l,n_{s}}(m)} = {{\frac{1}{\sqrt{2}}\left( {1 - {2 \cdot {c\left( {2m} \right)}}} \right)} + {j\frac{1}{\sqrt{2}}\left( {1 - {2 \cdot {c\left( {{2m} + 1} \right)}}} \right)}}},{m = 0},1,\ldots\mspace{11mu},{N_{RB}^{\max,{DL}} - 1}} & (16) \\{\mspace{79mu}{{c(n)} = {\left( {{x_{1}\left( {n + N_{C}} \right)} + {x_{2}\left( {n + N_{C}} \right)}} \right){{mod}2}}}} & (17) \\{\mspace{79mu}{{x_{1}\left( {n + 31} \right)} = {\left( {{x_{1}\left( {n + 3} \right)} + {x_{1}(n)}} \right){{mod}2}}}} & (18) \\{\mspace{79mu}{{x_{2}\left( {n + 31} \right)} = {\left( {{x_{2}\left( {n + 3} \right)} + {x_{2}\left( {n + 2} \right)} + {x_{2}\left( {n + 1} \right)} + {x_{2}(n)}} \right){{mod}2}}}} & (19)\end{matrix}$where n_(s) is a timeslot number in a radio frame, and l is an OFDMsymbol number in a timeslot. An initial value of the pseudo randomsequence c(i) may be set according to specific implementation.

Optionally, the reference signal sequence may be obtained by means ofcyclic shift according to a root sequence, for example, obtainedaccording to the following formula:r _(l,n) _(s) (m)=x _(u)((m+v)mod N _(ZC) ^(RS))  (20)

The base sequence is generated according to r_(u)(n)=x_(u)(n mod N_(ZC)^(RS)), where x_(u)(n) is a root sequence of a root index value u,N_(RS) is a length of the reference signal sequence, and v is a CSvalue.

Optionally, the reference signal sequence may be obtained according to acombination of two base sequences, for example, obtained according tothe following formula:r _(l,n) _(s) (m)=r(m)x _(u)(m)  (21)wherer(m)=e ^(jαm) and α=2πn _(cs) /M, 0≤n _(cs) <M.

Specifically, for a different sounding signal type, the resourceconfiguration index determining module 120 determines the referencesignal resource configuration index according to the sounding signal setin the following specific implementation manners:

Type 1: The sounding signal is a CRS or a channel state informationreference signal CSI RS, and the reference signal resource configurationindex includes a first rank indicator (RI₁) and/or a PMI₁. Specifically,the determining, by the resource configuration index determining module120, the RI₁ and/or the PMI₁ according to the CRS or the CSI RSincludes: obtaining, by the resource configuration index determiningmodule 120, a channel estimation value according to the CRS or the CSIRS; and selecting, by the resource configuration index determiningmodule 120, through the obtained channel estimation value, a firstprecoding matrix from a first codebook according to a preset criterion,where the first precoding matrix corresponds to the RI₁ and/or the PMI₁.

The channel estimation may be implemented according to the prior aft,for example, by using the LS method or the minimum mean squared errormethod.

The preset criterion may be a criterion such as capacity maximization ormutual information maximization or throughput maximization, which is notlimited in the present disclosure.

The first codebook is a precoding matrix set, in which each firstprecoding matrix is referred to as a codeword, and each codeword may beindicated by the RI₁ and/or the PMI₁.

Optionally, in an embodiment, the resource configuration indexdetermining module 120 determines that a precoding matrix included inthe first codebook used by the first precoding matrix is a precodingmatrix in a 2-antenna codebook, a 4-antenna codebook, or an 8-antennacodebook in the LTE R10 system, or is a precoding matrix in a 2-antennacodebook, a 4-antenna codebook, or an 8-antenna codebook in an LTE R12system.

In this embodiment of the present disclosure, optionally, as an example,a precoding matrix included in the first codebook is a discrete Fouriertransform (DFT) matrix, a Hadamard matrix, a Householder matrix, akronecker product of two DFT matrices, a kronecker product of a DFTmatrix and a Hadamard matrix, or a kronecker product of a DFT matrix anda Householder matrix.

It should be pointed out that the precoding matrix in the first codebookmay be pre-stored on a user equipment side or on a base station side, ormay be calculated according to a structure of the precoding matrix, forexample, calculated according to a relationship between the firstprecoding matrix indicator and the precoding matrix, which, however, isnot limited in the present disclosure.

Selecting a precoding matrix according to a channel estimation by usinga preset criterion is the prior art, and is not further describedherein.

A correspondence between the RI₁ and/or the PMI₁ included in thereference signal resource configuration index and the reference signalresource configuration information may be predefined or may be notifiedby the base station to the user equipment by using higher layersignaling such as RRC signaling or downlink control information (DCI),which is specifically shown in Table 1 or Table 2.

TABLE 1 Precoding Reference signal resource configuration matrix AntennaReference signal Reference signal indicator port configuration sequencePMI₁ information information information 0 8 0 0 1 8 0 1 2 8 1 0 3 8 1 14 8 2 0 5 8 2 1 6 8 3 0 7 8 3 1

TABLE 2 Precoding Reference signal resource configuration Rank matrixAntenna Reference signal Reference signal indicator indicator portconfiguration sequence RI PMI₁ information information information 1 0 80 0 1 8 0 1 2 8 1 0 3 8 1 1 4 8 2 0 5 8 2 1 6 8 3 0 7 8 3 1 2 0 16 0 0 116 0 1 2 16 1 0 3 16 1 1 4 16 2 0 5 16 2 1 6 16 3 0 7 16 3 1

The resource configuration index determining module 120 may obtain thecorresponding reference signal resource configuration according to thecorrespondence and according to the determined RI₁ and/or PMI₁ includedin the reference signal resource configuration index.

Further, the CRS or the CSI RS is specified by a specific referencesignal resource configuration in the reference signal resourceconfiguration set information. For example, the CRS or the CSI RS isalways specified by using the first reference signal resourceconfiguration in the reference signal resource configuration setinformation.

Type 2: The sounding signal is a synchronization signal, and thereference signal resource configuration index is a resource identifiercarried in the synchronization signal or associated with a resourcelocation of the synchronization signal, where the resource identifiercarried in the synchronization signal or associated with the resourcelocation of the synchronization signal indicates a reference signalresource configuration in the reference signal resource configurationset information. Optionally, a different resource identifier carried inthe synchronization signal is denoted by a different synchronizationsignal sequence. Specifically, the resource identifier may be denoted bythe different synchronization signal sequence. For example, as mentionedabove, the synchronization signal sequence is a ZC sequence, andtherefore, a different resource identifier may correspond to a differentroot index value or a different cyclic shift value of the ZC sequence.For example, as mentioned above, the synchronization signal sequence isan m sequence or a Gold sequence or a combination thereof, andtherefore, a different resource identifier may correspond to a differentm sequence or Gold sequence, or a combination thereof, or a differentinitial value thereof, or a different cyclic shift value thereof.

The resource configuration index determining module 120 may directlydetermine, by detecting and determining a synchronization channel whosechannel condition is favorable to the resource configuration indexdetermining module 120, the reference signal resource configurationindex corresponding to the sounding signal according to thesynchronization signal or the resource identifier of the synchronizationsignal. Implementing time or frequency synchronization by using thestructure of the synchronization signal and the correspondingsynchronization signal sequence is the prior aft, and is not describedherein. In addition, selecting a synchronization signal whose channelcondition is favorable to the resource configuration index determiningmodule 120 may be implemented based on receive power, and is not limitedherein.

Type 3: The sounding signal is a broadcast channel. The reference signalresource configuration index is a resource identifier carried in thebroadcast channel or associated with a resource location of thebroadcast channel, where the resource identifier carried in thebroadcast channel or associated with the resource location of thebroadcast channel indicates a reference signal resource configuration inthe reference signal resource configuration set information.

Optionally, the resource identifier carried in the broadcast channel maybe carried in a broadcast message of a different resource element set,where a broadcast message of a different resource element set carries adifferent resource identifier. By means of detection and decoding toobtain a corresponding broadcast message, the resource configurationindex determining module 120 can obtain the corresponding resourceidentifier.

Optionally, the resource identifier carried in the broadcast channel isdenoted by a different cyclic redundancy check mask. By means ofdetection and decoding, the user equipment obtains the correspondingbroadcast channel, and then performs a hypothesis test on the used CRCmask to obtain the corresponding CRC mask, so as to obtain thecorresponding resource identifier. In addition, in the foregoing twoimplementations, the user equipment obtains, by detecting a broadcastchannel whose channel condition is favorable to the user equipment, aresource identifier whose channel condition is favorable to the userequipment.

Receiving the broadcast channel by using the structure of the broadcastchannel and the corresponding CRC is the prior aft, and is not describedherein. In addition, selecting a broadcast channel whose channelcondition is favorable to the user equipment may be implemented based onreceive power, and is not limited herein.

Optionally, a correspondence between the reference signal resourceconfiguration index and the indicated reference signal resourceconfiguration is predefined or is notified to the user equipment byusing higher layer signaling or DCI.

The reference signal set receiving module 130 is configured to receive areference signal set sent by the base station, where the referencesignal set corresponds to the reference signal resource configurationindicated by the reference signal resource configuration index.

Specifically, the reference signal set receiving module 130 may receiveonly the reference signal set corresponding to the reference signalresource configuration indicated by the reference signal resourceconfiguration index.

The channel state information determining module 140 is configured todetermine channel state information according to the reference signalset.

Specifically, the channel state information may include a CQI, a PMI, oran RI. The determining, by the channel state information determiningmodule 140, channel state information CSI according to the referencesignal set may include: obtaining, by the channel state informationdetermining module 140, a channel estimation value according to thereference signal set; and determining, by the channel state informationdetermining module 140, the CSI based on a preset criterion andaccording to the obtained channel estimation value.

Further, a specific implementation manner of determining, by the channelstate information determining module 140, channel state informationaccording to the reference signal set may be: determining a secondprecoding matrix indicator (PMI₂) according to the reference signal set,where the PMI₂ corresponds to a precoding matrix selected from a secondcodebook, the second codebook is determined according to the referencesignal resource configuration index, and the channel state informationincludes the PMI₂.

Specifically, the second codebook may be determined according to thereference signal resource configuration index. For example, differentcodebooks may be determined according to a correspondence between areference signal resource configuration index and a codebook, where thecorrespondence is shown in Table 3, in which C_(N,i) may be the i^(th)codebook of N antenna ports, where N=4 or 8.

TABLE 3 Reference signal resource configuration index Codebook 0 C_(4,0)1 C_(4,1) 2 C_(4,2) 3 C_(4,3) 4 C_(8,0) 5 C_(8,1) 6 C_(8,2) 7 C_(8,3)

Using a 4-antenna codebook as an example, a precoding matrix in C_(4,0)may be a matrix in a 4-antenna codebook in an LTE system such as an R8or R11 system, and a precoding matrix in C_(4,i) may be:W _(i)=diag{1,e ^(jθ) ,e ^(jθ) ,e ^(j(φ+θ)) }W ₀  (22)

where matrices W₀ and W_(i) may be a matrix in C_(4,0) and a matrix inC_(4,i) respectively, and θ,φ are phases. For example,

${\theta = \frac{\pi}{64}},\frac{\pi}{32},{\frac{\pi}{16}\mspace{14mu}\ldots}\mspace{11mu},{\varphi = \pi},\frac{\pi}{2},\frac{\pi}{4},\ldots\mspace{11mu},.$

Optionally, in an embodiment, the precoding matrix included in thesecond codebook is a discrete Fourier transform (DFT) matrix, a Hadamardmatrix, a Householder matrix, a kronecker product of two DFT matrices, aproduct of a DFT matrix and a Hadamard matrix, or a kronecker product ofa DFT matrix and a Householder matrix.

In addition, the channel estimation may be implemented according to theprior art, for example, by using the least square method or the minimummean squared error method. The preset criterion may be a criterion suchas capacity maximization or mutual information maximization orthroughput maximization, which is not limited in the present disclosure.Selecting a precoding matrix according to a channel estimation by usinga preset criterion is the prior art, and is not further describedherein.

It should be pointed out that the precoding matrix in the secondcodebook may be pre-stored on the user equipment side or on the basestation side, or may be calculated according to the structure of theprecoding matrix, for example, calculated according to a relationshipbetween the second precoding matrix indicator and the precoding matrix,which, however, is not limited in the present disclosure.

The channel state information sending module 150 is configured to sendthe reference signal resource configuration index and the channel stateinformation to the base station.

Specifically, the channel state information sending module 150 sends thereference signal resource configuration index and reports the channelstate information to the base station.

Optionally, the channel state information sending module 150 may sendthe reference signal resource configuration index and the channel stateinformation to the base station separately on a same subframe or ondifferent subframes.

Further, optionally, a period of sending the reference signal resourceconfiguration index is longer than a period of sending the channel stateinformation. The reference signal resource configuration index isactually used to indicate a CSI measurement reference signal, thesounding signal generally has stronger spatial correlation, timecorrelation, or frequency correlation than the antenna portcorresponding to the signal set, and a channel state changes relativelyslowly. Therefore, a time interval or span of sending the referencesignal resource configuration index may be longer, so as to furtherreduce time-frequency resource overheads occupied for sending of thesounding signal and reduce complexity of implementation by the UE.

Referring to FIG. 4, as shown in the figure, the user equipment in thisembodiment of the present disclosure may further include a resourceconfiguration set receiving module 160, configured to receive thereference signal resource configuration set information sent by the basestation, where the reference signal resource configuration setinformation includes at least two reference signal resourceconfigurations.

The reference signal resource configuration set information may also bepredefined and known by both the user equipment and the base station.

The reference signal resource configuration set information includes atleast two reference signal resource configurations. Referring to Table4, Table 4 is an expression form of the reference signal resourceconfiguration set information. As shown in the table, there are eightdifferent reference signal resource configurations in the table. Areference signal resource configuration may include at least antennaport information and reference signal configuration information, wherethe reference signal configuration information is used to indicate aresource element used for sending a reference signal on an antenna port,and the antenna port information is a quantity of antenna portscorresponding to one of the reference signal configurations.

TABLE 4 Reference Reference signal resource configuration signal setinformation resource Quantity of configuration antenna Reference signalindex ports configuration information 0 4 0 1 4 1 2 4 2 3 4 3 4 8 0 5 81 6 8 2 7 8 3

Optionally, the reference signal resource configuration set informationmay further include reference signal sequence information. For example,as shown in Table 5, the reference signal resource configuration indexes0, 1, 2, and 3 support four antenna ports, and use a same referencesignal configuration 0. That is, they occupy a same resource element butdifferent reference signal sequences 0, 1, 2, and 3. Antennascorresponding to the different reference signal sequences 0, 1, 2, and 3may be implemented by using different beams, and the different beams maybe orthogonal to each other. On the one hand, using the same resourceelement can avoid occupying too many time-frequency resources, therebyeffectively saving overheads. On the other hand, sending the differentreference signal sequences 0, 1, 2, and 3 by the different beams mayeffectively reduce interference between different reference signals,thereby improving channel estimation precision and ensuring CSImeasurement precision.

TABLE 5 Reference signal Reference signal resource configuration setinformation resource Reference signal Reference signal configurationQuality of configuration sequence index antenna ports informationinformation 0 4 0 0 1 4 0 1 2 4 0 2 3 4 0 3

Specially, the reference signal resource configuration may have, but notbeing limited to, the following characteristics:

Characteristic 1: Antenna port sets corresponding to two referencesignal resource configurations have at least one same antenna port.Specifically, using the reference signal resource configurationinformation in Table 4 as an example, reference signal configurationscorresponding to the reference signal configuration information maycorrespond to different antenna port sets. As shown in Table 6, everytwo adjacent antenna port sets in 4-antenna-port sets have two sameantenna ports, and every two adjacent antenna port sets in8-antenna-port sets have four same antenna ports. On the one hand, thesystem can support more antenna ports. On the other hand, every tworeference signal configurations configured by the user equipment have atleast one same antenna port, so as to overcome a coverage gap betweenantenna ports and overcome an edge effect.

TABLE 6 Reference signal resource Reference signal configurationinformation configuration Quantity of index antenna ports Antenna portset 0 4 {0, 1, 2, 3} 1 4 {2, 3, 4, 5} 2 4 {4, 5, 6, 7} 3 4 {6, 7, 0, 1}4 8 {0, 1, 2, . . . , 7} 5 8 {4, 5, 6, . . . , 11} 6 8 {8, 9, 10, . . ., 15} 7 8 {12, 13, 14, . . . , 19}

Characteristic 2: The reference signal sequence information is aninitial value or cyclic shift value of a reference signal sequence, ordifferent combinations of two base sequences. Specifically, thereference signal sequence information is different initial values orcyclic shift values of the reference signal sequence, or differentcombinations of two base sequences, as described above.

Characteristic 3: A different antenna port corresponding to eachreference signal resource configuration uses a different resourcereference signal configuration or a different reference signal sequence,as described above.

FIG. 5 is a schematic structural diagram of a base station according toan embodiment of the present disclosure. As shown in the figure, thebase station in this embodiment of the present disclosure may include atleast a sounding signal set sending module 210, a reference signal setsending module 220, and a channel state information receiving module230.

The sounding signal set sending module 210 is configured to send asounding signal set to user equipment, where the sounding signal setincludes at least one sounding signal, so that the user equipmentdetermines a reference signal resource configuration index according tothe sounding signal set, where the reference signal resourceconfiguration index is used to indicate a reference signal resourceconfiguration in reference signal resource configuration setinformation.

In a first optional implementation manner, the sounding signal is acell-specific reference signal (CRS) or a channel state informationreference signal (CSI RS). The CRS may support a cell-specific antennaport configuration, and is received by all user equipments in this cell.For example, the CRS may be a reference signal corresponding to anantenna port 0, 1, 2, or 3 in an LTE R8 system. The CSI RS supportssignal transmission on a cell-specific antenna port and signal receivingon a user equipment specific antenna port. For example, the CSI RS maybe a reference signal corresponding to an antenna port 15, 16, . . . ,or 22 in an LTE R10 system. It should be pointed out that the CRS or theCSI RS is not limited to a current LTE system.

In a second optional implementation manner, the sounding signal is asynchronization signal. The synchronization signal is used to implementtime and frequency synchronization. One of multiple known or optionalsynchronization signal sequences is mapped to a resource element set ofa synchronization signal. According to the known or optionalsynchronization signal sequence, the user equipment may implement timeand frequency synchronization by detecting the synchronization signal.

Specifically, the synchronization signal may be sent on at least oneresource element set separately. For example, using a frame structure inan LTE system as an example, the at least one resource element set maybe shown by formulas (1) and (2).

The triplet (k, l, n_(s)) denotes a location of a resource element usedfor the synchronization signal, where k, l, and n_(s) are respectively asubcarrier index, an OFDM symbol index, and a timeslot index of theresource element; N_(SS) denotes a length of a synchronization signalsequence.

Specifically, in each resource element set, the synchronization signalsends a synchronization signal sequence. The synchronization signalsequence may be a Zadoff-Chu (ZC) sequence. Using N_(SS)=62 as anexample, the synchronization signal sequence is a ZC sequence shown byformula (3) or a cyclic shift of the ZC sequence shown by formula (4),where the parameter u is a root index of the ZC sequence, and its valuemay be, for example, 25, 29, or 34; the parameter v is a cyclic shiftvalue, and its value may be, for example, a positive integer such as 3or 6.

Optionally, the synchronization signal sequence may also be an msequence or a Gold sequence or a combination thereof, and is not furtherenumerated herein.

Specifically, the synchronization signal sequence may be separatelymapped to different resource element sets. Using the ZC sequence whoselength is 62 as an example, 62 elements in the sequence may be mapped to62 resource element locations respectively. For example, a sequenceelement in an RE location (k, l, n_(s)) in the resource element setS_(i) ^(SS) is formula (5) or (6), where u_(i) and v_(i) arerespectively a root index value and a cyclic shift value of a ZCsequence used for the synchronization signal on the resource element setS_(i) ^(SS). A synchronization signal on a different resource elementset S_(i) ^(SS) may use a different root index value or a differentcyclic shift value or a combination thereof. It should be pointed outthat a different u_(i) or v_(i) or a combination (u_(i),v_(i)) thereofmay correspond to a different piece of information, so that thesynchronization signal sent on the different resource element setscarries different information.

In a third optional implementation manner, the sounding signal is abroadcast channel. The broadcast channel is used to send a broadcastmessage. The broadcast message may include, for example, a systembandwidth, a system frame number, physical channel configurationindication information, or a combination thereof.

Specifically, the broadcast channel may be sent on at least one resourceelement set separately. For example, using a frame structure in an LTEsystem as an example, the at least one resource element set may be shownby formulas (7) and (8) or formulas (9) and (10), where the quadruplet(k, l, n_(s), n_(f)) denotes a location of a resource element used forthe broadcast channel, where k, l, n_(s), and n_(f) are respectively asubcarrier index, an OFDM symbol index, a timeslot index, and a systemframe number of the resource element; j₀≠j₁, and value ranges of allparameters j, j₀, and j₁ are 0, 1, . . . , 4N−1. The positive integer Nin formulas (7) to (10) may be 1 or a positive integer greater than 1.

Specifically, a broadcast channel sent by each resource element groupmay be mapped to a corresponding resource element set after undergoingchannel coding (by using a convolutional code or a Turbo code) andmodulation. In addition, before channel coding, a cyclic redundancycheck (CRC) code may be appended to the broadcast message.

Optionally, the broadcast channels in the different resource elementsets may further carry additional information separately in addition tothe system broadcast information. Optionally, an implementation mannermay be:

Manner 1: The additional information and the broadcast information forma broadcast message, and undergo processing such as channel coding.

Manner 2: The additional information is denoted by a different CRC mask.Specifically, a CRC check bit corresponding to the broadcast messagecarried in the broadcast channel is p_(n), n=0, 1, 2, . . . , N_(CRC)−1,and a CRC mask corresponding to the indication information is x_(n),n=0, 1, 2, . . . , N_(CRC)−1. Therefore, after CRC mask scrambling, bitsequences shown by formulas (11) to (15) are generated.

It should be specially noted that the foregoing three implementationmanners merely show three specific sounding signal types proposed inthis embodiment of the present disclosure. However, type of the soundingsignal is not limited thereto, and is not enumerated exhaustivelyherein.

The user equipment determines the reference signal resourceconfiguration index according to the sounding signal set in thefollowing specific implementation manners:

Type 1: The sounding signal is a CRS or a channel state informationreference signal CSI RS, and the reference signal resource configurationindex includes a RI₁ and/or a PMI₁. Specifically, the determining, bythe user equipment, the RI₁ and/or the PMI₁ according to the CRS or theCSI RS includes: obtaining, by the user equipment, a channel estimationvalue according to the CRS or the CSI RS; and obtaining, by the userequipment, the channel estimation value, and selecting a first precodingmatrix from a first codebook according to a preset criterion, where thefirst precoding matrix corresponds to the RI₁ and/or the PMI₁.

The channel estimation may be implemented according to the prior art,for example, by using the least square method or the minimum meansquared error method.

The preset criterion may be a criterion such as capacity maximization ormutual information maximization or throughput maximization, which is notlimited in the present disclosure.

The first codebook is a precoding matrix set, in which each firstprecoding matrix is referred to as a codeword, and each codeword may beindicated by the RI₁ and/or the PMI₁.

Optionally, in an embodiment, the user equipment determines that aprecoding matrix included in the first codebook used by the firstprecoding matrix is a precoding matrix in a 2-antenna codebook, a4-antenna codebook, or an 8-antenna codebook in the LTE R10 system, oris a precoding matrix in a 2-antenna codebook, a 4-antenna codebook, oran 8-antenna codebook in an LTE R12 system.

In this embodiment of the present disclosure, optionally, as anembodiment, a precoding matrix included in the first codebook is adiscrete Fourier transform (DFT) matrix, a Hadamard matrix, aHouseholder matrix, a kronecker product of two DFT matrices, a kroneckerproduct of a DFT matrix and a Hadamard matrix, or a kronecker product ofa DFT matrix and a Householder matrix.

It should be pointed out that the precoding matrix in the first codebookmay be pre-stored on a user equipment side or on a base station side, ormay be calculated according to a structure of the precoding matrix, forexample, calculated according to a relationship between the firstprecoding matrix indicator and the precoding matrix, which, however, isnot limited in the present disclosure.

Selecting a precoding matrix according to a channel estimation by usinga preset criterion is the prior art, and is not further describedherein.

A correspondence between the RI₁ and/or the PMI₁ included in thereference signal resource configuration index and the reference signalresource configuration information may be predefined or may be notifiedby the base station to the user equipment by using higher layersignaling such as RRC signaling or DCI, which is specifically shown inTable 1 or Table 2.

The user equipment may obtain the corresponding reference signalresource configuration according to the correspondence and according tothe determined RI₁ and/or PMI₁ included in the reference signal resourceconfiguration index.

Further, the CRS or the CSI RS is specified by a specific referencesignal resource configuration in the reference signal resourceconfiguration set information. For example, the CRS or the CSI RS isalways specified by using the first reference signal resourceconfiguration in the reference signal resource configuration setinformation.

Type 2: The sounding signal is a synchronization signal, and thereference signal resource configuration index is a resource identifiercarried in the synchronization signal or associated with a resourcelocation of the synchronization signal, where the resource identifiercarried in the synchronization signal or associated with the resourcelocation of the synchronization signal indicates a reference signalresource configuration in the reference signal resource configurationset information. Optionally, a different resource identifier carried inthe synchronization signal is denoted by a different synchronizationsignal sequence. Specifically, the resource identifier may be denoted bythe different synchronization signal sequence. For example, as mentionedabove, the synchronization signal sequence is a ZC sequence, andtherefore, a different resource identifier may correspond to a differentroot index value or a different cyclic shift value of the ZC sequence.For example, as mentioned above, the synchronization signal sequence isan m sequence or a Gold sequence or a combination thereof, andtherefore, a different resource identifier may correspond to a differentm sequence or Gold sequence, or a combination thereof, or a differentinitial value thereof, or a different cyclic shift value thereof.

The user equipment may directly determine, by detecting and determininga synchronization channel whose channel condition is favorable to theuser equipment, the reference signal resource configuration indexcorresponding to the sounding signal according to the synchronizationsignal or the resource identifier of the synchronization signal.Implementing time or frequency synchronization by using the structure ofthe synchronization signal and the corresponding synchronization signalsequence is the prior art, and is not described herein. In addition,selecting a synchronization signal whose channel condition is favorableto the user equipment may be implemented based on receive power, and isnot limited herein.

Type 3: The sounding signal is a broadcast channel. The reference signalresource configuration index is a resource identifier carried in thebroadcast channel or associated with a resource location of thebroadcast channel, where the resource identifier carried in thebroadcast channel or associated with the resource location of thebroadcast channel indicates a reference signal resource configuration inthe reference signal resource configuration set information.

Optionally, the resource identifier carried in the broadcast channel maybe carried in a broadcast message of a different resource element set,where a broadcast message of a different resource element set carries adifferent resource identifier. By means of detection and decoding toobtain a corresponding broadcast message, the user equipment can obtainthe corresponding resource identifier.

Optionally, the resource identifier carried in the broadcast channel isdenoted by a different cyclic redundancy check mask. By means ofdetection and decoding, the user equipment obtains the correspondingbroadcast channel, and then performs a hypothesis test on the used CRCmask to obtain the corresponding CRC mask, so as to obtain thecorresponding resource identifier. In addition, in the foregoing twoimplementations, the user equipment obtains, by detecting a broadcastchannel whose channel condition is favorable to the user equipment, aresource identifier whose channel condition is favorable to the userequipment.

Receiving the broadcast channel by using the structure of the broadcastchannel and the corresponding CRC is the prior art, and is not describedherein. In addition, selecting a broadcast channel whose channelcondition is favorable to the user equipment may be implemented based onreceive power, and is not limited herein.

Optionally, a correspondence between the reference signal resourceconfiguration index and the indicated reference signal resourceconfiguration is predefined or is notified to the user equipment byusing higher layer signaling or DCI.

The reference signal set sending module 220 is configured to send atleast two reference signal sets to the user equipment, where the atleast two reference signal sets correspond to at least two referencesignal resource configurations included in the reference signal resourceconfiguration set information, so that the user equipment determines achannel state according to the reference signal set.

The channel state information may include a CQI, a PMI, or an RI. Thedetermining, by the user equipment, channel state information CSIaccording to the reference signal set may include: obtaining, by theuser equipment, a channel estimation value according to the referencesignal set.

Further, a specific implementation manner of determining, by the userequipment, channel state information according to the reference signalset may be: determining a PMI₂ according to the reference signal set,where the PMI₂ corresponds to a precoding matrix selected from a secondcodebook, the second codebook is determined according to the referencesignal resource configuration index, and the channel state informationincludes the PMI₂.

Specifically, the second codebook may be determined according to thereference signal resource configuration index. For example, differentcodebooks may be determined according to a correspondence between areference signal resource configuration index and a codebook, where thecorrespondence is shown in Table 3, in which C_(N,i) may be the i^(th)codebook of N antenna ports, where N=4 or 8.

Using a 4-antenna codebook as an example, a precoding matrix in C_(4,0)may be a matrix in a 4-antenna codebook in an LTE system such as an R8or R11 system, and a precoding matrix in C_(4,i) may be shown by formula(22), where matrices W₀ and W_(i) may be a matrix in C_(4,0) and amatrix in C_(4,i) respectively, and θ,φ are phases. For example,

${\theta = \frac{\pi}{64}},\frac{\pi}{32},{\frac{\pi}{16}\mspace{14mu}\ldots}\mspace{11mu},{\varphi = \pi},\frac{\pi}{2},\frac{\pi}{4},\ldots\mspace{11mu},.$

Optionally, in an embodiment, the precoding matrix included in thesecond codebook is a discrete Fourier transform DFT matrix, a Hadamardmatrix, a Householder matrix, a kronecker product of two DFT matrices, akronecker product of a DFT matrix and a Hadamard matrix, or a kroneckerproduct of a DFT matrix and a Householder matrix.

In addition, the channel estimation may be implemented according to theprior art, for example, by using the least square method or the minimummean squared error method. The preset criterion may be a criterion suchas capacity maximization or mutual information maximization orthroughput maximization, which is not limited in the present disclosure.Selecting a precoding matrix according to a channel estimation by usinga preset criterion is the prior art, and is not further describedherein.

It should be pointed out that the precoding matrix in the secondcodebook may be pre-stored on the user equipment side or on the basestation side, or may be calculated according to the structure of theprecoding matrix, for example, calculated according to a relationshipbetween the second precoding matrix indicator and the precoding matrix,which, however, is not limited in the present disclosure.

The channel state information receiving module 230 is configured toreceive the reference signal resource configuration index and thechannel state information that are sent by the user equipment.

Optionally, the channel state information receiving module 230 mayreceive the reference signal resource configuration index and thechannel state information that are sent by the user equipment on a samesubframe or on different subframes separately.

Further, optionally, a period of sending the reference signal resourceconfiguration index is longer than a period of sending the channel stateinformation. The reference signal resource configuration index isactually used to indicate a CSI measurement reference signal, thesounding signal generally has stronger spatial correlation, timecorrelation, or frequency correlation than the antenna portcorresponding to the signal set, and a channel state changes relativelyslowly. Therefore, a time interval or span of sending the referencesignal resource configuration index may be longer, so as to furtherreduce time-frequency resource overheads occupied for sending of thesounding signal and reduce complexity of implementation by the UE.

Referring to FIG. 5, as shown in the figure, the base station in thisembodiment of the present disclosure may further include a resourceconfiguration set sending module 240, configured to send the referencesignal resource configuration set information to the user equipment,where the reference signal resource configuration set informationincludes the at least two reference signal resource configurations.

Specifically, the resource configuration set sending module 240 maynotify the user equipment of the reference signal resource configurationset information by using higher layer signaling such as RRC signaling orDCI, and the reference signal resource configuration set information mayalso be predefined and known by both the user equipment and the basestation.

The reference signal resource configuration set information includes atleast two reference signal resource configurations. Referring to Table4, Table 4 is an expression form of the reference signal resourceconfiguration set information. As shown in the table, there are eightdifferent reference signal resource configurations in the table. Areference signal resource configuration may include at least antennaport information and reference signal configuration information, wherethe reference signal configuration information is used to indicate aresource element used for sending a reference signal on an antenna port,and the antenna port information is a quantity of antenna portscorresponding to one of the reference signal configurations.

Optionally, the reference signal resource configuration set informationmay further include reference signal sequence information. For example,as shown in Table 5, the reference signal resource configuration indexes0, 1, 2, and 3 support four antenna ports, and use a same referencesignal configuration 0. That is, they occupy a same resource element butdifferent reference signal sequences 0, 1, 2, and 3. Antennascorresponding to the different reference signal sequences 0, 1, 2, and 3may be implemented by using different beams, and the different beams maybe orthogonal to each other. On the one hand, using the same resourceelement can avoid occupying too many time-frequency resources, therebyeffectively saving overheads. On the other hand, sending the differentreference signal sequences 0, 1, 2, and 3 by the different beams mayeffectively reduce interference between different reference signals,thereby improving channel estimation precision and ensuring CSImeasurement precision.

Specially, the reference signal resource configuration may have, but notbeing limited to, the following characteristics.

Characteristic 1: Antenna port sets corresponding to two referencesignal resource configurations have at least one same antenna port.Specifically, using the reference signal resource configurationinformation in Table 4 as an example, reference signal configurationscorresponding to the reference signal configuration information maycorrespond to different antenna port sets. As shown in Table 6, everytwo adjacent antenna port sets in 4-antenna-port sets have two sameantenna ports, and every two adjacent antenna port sets in8-antenna-port sets have four same antenna ports. On the one hand, thesystem can support more antenna ports. On the other hand, every tworeference signal configurations configured by the user equipment have atleast one same antenna port, so as to overcome a coverage gap betweenantenna ports and overcome an edge effect.

Characteristic 2: The reference signal sequence information is aninitial value or cyclic shift value of a reference signal sequence, ordifferent combinations of two base sequences. Specifically, thereference signal sequence information is different initial values orcyclic shift values of the reference signal sequence, or differentcombinations of two base sequences, as described above.

Characteristic 3: A different antenna port corresponding to eachreference signal resource configuration uses a different resourcereference signal configuration or a different reference signal sequence,as described above.

FIG. 6 is a schematic structural diagram of user equipment according toanother embodiment of the present disclosure. As shown in FIG. 6, theuser equipment may include at least one processor 301, for example, aCPU, at least one transceiver antenna 303, a memory 304, and at leastone communications bus 302. The communications bus 302 is configured toimplement connection and communication between these components. Thetransceiver antenna 303 may be configured to perform signaling or datacommunication with another node device. The memory 304 may be ahigh-speed RAM memory, or may be a non-volatile memory (non-volatilememory), for example, at least one magnetic disk memory. Optionally, thememory 304 may be at least one storage apparatus located far away fromthe processor 301. The memory 304 stores a set of program code, and theprocessor is configured to invoke the program code stored in the memoryto perform the following operations: receiving a sounding signal setsent by the base station, where the sounding signal set includes atleast one sounding signal; determining a reference signal resourceconfiguration index according to the sounding signal set, where thereference signal resource configuration index is used to indicate areference signal resource configuration in reference signal resourceconfiguration set information; receiving a reference signal set sent bythe base station, where the reference signal set corresponds to thereference signal resource configuration indicated by the referencesignal resource configuration index; determining channel stateinformation according to the reference signal set; and sending thereference signal resource configuration index and the channel stateinformation to the base station.

Optionally, before the determining, by the processor 301, a referencesignal resource configuration index according to the sounding signalset, the following operation is further included: receiving thereference signal resource configuration set information sent by the basestation, where the reference signal resource configuration setinformation includes at least two reference signal resourceconfigurations.

Optionally, the determining, by the processor 301, channel stateinformation according to the reference signal set is specifically:determining a PMI₂ according to the reference signal set, where the PMI₂corresponds to a precoding matrix selected from a codebook, and thecodebook is determined according to the reference signal resourceconfiguration index; and the channel state information includes thePMI₂.

FIG. 7 is a schematic structural diagram of a base station according toanother embodiment of the present disclosure. As shown in FIG. 7, thebase station may include at least one processor 401, for example, a CPU,multiple transceiver antennas 403, a memory 404, and at least onecommunications bus 402. The communications bus 402 is configured toimplement connection and communication between these components. Thetransceiving antenna 403 may be configured to perform signaling or datacommunication with another node device. The memory 404 may be ahigh-speed RAM memory, or may be a non-volatile memory, for example, atleast one magnetic disk memory. Optionally, the memory 404 may be atleast one storage apparatus located far away from the processor 401. Thememory 404 stores a set of program code, and the processor is configuredto invoke the program code stored in the memory to perform the followingoperations: sending a sounding signal set to user equipment, where thesounding signal set includes at least one sounding signal, so that theuser equipment determines a reference signal resource configurationindex according to the sounding signal set, where the reference signalresource configuration index is used to indicate a reference signalresource configuration in reference signal resource configuration setinformation; sending at least two reference signal sets to the userequipment, where the at least two reference signal sets correspond to atleast two reference signal resource configurations included in thereference signal resource configuration set information; and receivingthe reference signal resource configuration index and channel stateinformation that are sent by the user equipment, where the channel stateinformation is obtained by the user equipment according to a referencesignal resource configuration indicated by the reference signal resourceconfiguration index.

Optionally, the processor 401 further includes: sending the referencesignal resource configuration set information to the user equipment,where the reference signal resource configuration set informationincludes the at least two reference signal resource configurations.

FIG. 8 is a schematic flowchart of a method for reporting channel stateinformation according to an embodiment of the present disclosure. Asshown in the figure, a procedure of the method for reporting channelstate information in this embodiment may include.

S501. User equipment receives a sounding signal set sent by a basestation.

Specifically, the sounding signal set includes at least one soundingsignal. It should be pointed out that.

In a first optional implementation manner, the sounding signal is acell-specific reference signal (CRS) or a channel state informationreference signal (CSI RS). The CRS may support a cell-specific antennaport configuration, and is received by all user equipments in this cell.For example, the CRS may be a reference signal corresponding to anantenna port 0, 1, 2, or 3 in an LTE R8 system. The CSI RS supportssignal transmission on a cell-specific antenna port and signal receivingon a user equipment specific antenna port. For example, the CSI RS maybe a reference signal corresponding to an antenna port 15, 16, . . . ,or 22 in an LTE R10 system. It should be pointed out that the CRS or theCSI RS is not limited to a current LTE system.

In a second optional implementation manner, the sounding signal is asynchronization signal. The synchronization signal is used to implementtime and frequency synchronization. One of multiple known or optionalsynchronization signal sequences is mapped to a resource element set ofa synchronization signal. According to the known or optionalsynchronization signal sequence, the user equipment may implement timeand frequency synchronization by detecting the synchronization signal.

Specifically, the synchronization signal may be sent on at least oneresource element set separately. For example, using a frame structure inan LTE system as an example, the at least one resource element set maybe shown by formula (1) or (2). The triplet (k, l, n_(s)) denotes alocation of a resource element used for the synchronization signal,where k, l, and n_(s) are respectively a subcarrier index, an OFDMsymbol index, and a timeslot index of the resource element; N_(SS)denotes a length of a synchronization signal sequence.

Specifically, in each resource element set, the synchronization signalsends a synchronization signal sequence. The synchronization signalsequence may be a Zadoff-Chu (ZC) sequence. Using N_(SS)=62 as anexample, the synchronization signal sequence is a ZC sequence shown byformula (3), or a cyclically shifted ZC sequence shown by formula (4).The parameter u is a root index of the ZC sequence, and its value maybe, for example, 25, 29, or 34; the parameter v is a cyclic shift value,and its value may be, for example, a positive integer such as 3 or 6.

Optionally, the synchronization signal sequence may also be an msequence or a Gold sequence or a combination thereof, and is not furtherenumerated herein.

Specifically, the synchronization signal sequence may be separatelymapped to different resource element sets. Using the ZC sequence whoselength is 62 as an example, 62 elements in the sequence may be mapped to62 resource element locations respectively. For example, a sequenceelement in an RE location (k, l, n_(s)) in the resource element setS_(i) ^(SS) is shown by formula (5) or formula (6), where u_(i) andv_(i) are respectively a root index value and a cyclic shift value of aZC sequence used for the synchronization signal on the resource elementset S_(i) ^(SS). A synchronization signal on a different resourceelement set S_(i) ^(SS) may use a different root index value or adifferent cyclic shift value or a combination thereof. It should bepointed out that a different u_(i) or v_(i) a combination (u_(i),v_(i))thereof may correspond to a different piece of information, so that thesynchronization signal sent on the different resource element setscarries different information.

In a third optional implementation manner, the sounding signal is abroadcast channel. The broadcast channel is used to send a broadcastmessage. The broadcast message may include, for example, a systembandwidth, a system frame number, physical channel configurationindication information, or a combination thereof.

Specifically, the broadcast channel may be sent on at least one resourceelement set separately. For example, using a frame structure in an LTEsystem as an example, the at least one resource element set may be shownby formulas (7) and (8) or formulas (9) and (10). The quadruplet (k, l,n_(s), n_(f)) denotes a location of a resource element used for thebroadcast channel, where k, l, n_(s), and n_(f) are respectively asubcarrier index, an OFDM symbol index, a timeslot index, and a systemframe number of the resource element; j₀≠j₁, and value ranges of allparameters j, j₀, and j₁ are 0 to 4N−1. The positive integer N informulas (7) to (10) may be 1 or a positive integer greater than 1.

Specifically, a broadcast channel sent by each resource element groupmay be mapped to a corresponding resource element set after undergoingchannel coding (by using a convolutional code or a Turbo code) andmodulation. In addition, before channel coding, a cyclic redundancycheck (CRC) code may be appended to the broadcast message.

Optionally, the broadcast channels in the different resource elementsets may further carry additional information separately in addition tothe system broadcast information. Optionally, an implementation mannermay be.

Manner 1: The additional information and the broadcast information forma broadcast message, and undergo processing such as channel coding.

Manner 2: The additional information is denoted by a different CRC mask(Mask). Specifically, a CRC check bit corresponding to the broadcastmessage carried in the broadcast channel is p_(n), n=0, 1, 2, . . . ,N_(CRC)−1, and a CRC mask corresponding to the indication information isx_(n), n=0, 1, 2, . . . , N_(CRC)−1. Therefore, after CRC maskscrambling, a bit sequence shown by formula (n) is generated.

For example, when N_(CRC)=16 or 24, four different CRC masks may beshown by formulas (12) to (15) respectively.

It should be specially noted that the foregoing three implementationmanners merely show three specific sounding signal types proposed inthis embodiment of the present disclosure. However, type of the soundingsignal is not limited thereto, and is not enumerated exhaustivelyherein.

S502. The user equipment determines a reference signal resourceconfiguration index according to the sounding signal set.

It should be pointed out that the reference signal resourceconfiguration index is used to indicate a reference signal resourceconfiguration in reference signal resource configuration setinformation. Generally, each reference signal corresponds to one antennaport. By means of a least square method, a minimum mean squared errormethod, or the like, a channel estimation on a corresponding antennaport may be obtained according to a resource element location occupiedby each reference signal in a resource grid of the corresponding antennaport.

Specifically, the reference signal resource configuration may includeinformation such as a supported quantity of antenna ports, a referencesignal sending period and an offset in the sending period, an RElocation occupied by a reference signal, or a reference signal sequence.The RE location occupied by the reference signal or a time-frequencypattern of the reference signal is generally referred to as a referencesignal configuration. Using 8 antenna ports as an example, RE locationscorresponding to the 8 antenna ports in frame structures FS1 and FS areshown in FIG. 2a and FIG. 2b respectively. Using 16 antenna ports as anexample, RE locations corresponding to the 16 antenna ports in the framestructures FS1 and FS are shown in FIG. 3a and FIG. 3b respectively.Using FIG. 3a as an example, RE locations denoted by digits 0, 1, . . ., 7 in the figure are locations occupied by reference signals.

Specifically, the reference signal sends a reference signal sequence onan occupied resource element set. Optionally, the reference signalsequence may be a ZC sequence or an m sequence, or may be obtainedaccording to a combination of two base sequences or according to apseudo random sequence, or the like.

For example, the reference signal sequence may be generated according toa pseudo random sequence, for example, as shown in formulas (16) to(19), where n_(s) is a timeslot number in a radio frame, and l is anOFDM symbol number in a timeslot. An initial value of the pseudo randomsequence c(i) may be set according to specific implementation.

Optionally, the reference signal sequence may be obtained by means ofcyclic shift according to a root sequence, for example, obtainedaccording to formula (20). The base sequence is generated according tor_(u)(n)=x_(u)(n mod N_(ZC) ^(RC)), where x_(u)(n) is a root sequence ofa root index value u, N_(RS) is a length of the reference signalsequence, and v is a CS value.

Optionally, the reference signal sequence may be obtained according to acombination of two base sequences, for example, obtained according toformula (21), where r(m)=e^(jαm) and α=2πn_(cs)/M, 0≤n_(cs)<M.

Optionally, the reference signal resource configuration set informationmay be sent by the base station to the user equipment when or beforestep S501 is performed. Specifically, the base station may notify theuser equipment of the reference signal resource configuration setinformation by using higher layer signaling such as RRC signaling orDCI.

The reference signal resource configuration set information may also bepredefined and known by both the user equipment and the base station.

The reference signal resource configuration set information includes atleast two reference signal resource configurations. Referring to Table4, Table 4 is an expression form of the reference signal resourceconfiguration set information. As shown in the table, there are eightdifferent reference signal resource configurations in the table. Areference signal resource configuration may include at least antennaport information and reference signal configuration information, wherethe reference signal configuration information is used to indicate aresource element used for sending a reference signal on an antenna port,and the antenna port information is a quantity of antenna portscorresponding to one of the reference signal configurations.

Optionally, the reference signal resource configuration set informationmay further include reference signal sequence information. For example,as shown in Table 5, the reference signal resource configuration indexes0, 1, 2, and 3 support four antenna ports, and use a same referencesignal configuration 0. That is, they occupy a same resource element butdifferent reference signal sequences 0, 1, 2, and 3. Antennascorresponding to the different reference signal sequences 0, 1, 2, and 3may be implemented by using different beams, and the different beams maybe orthogonal to each other. On the one hand, using the same resourceelement can avoid occupying too many time-frequency resources, therebyeffectively saving overheads. On the other hand, sending the differentreference signal sequences 0, 1, 2, and 3 by the different beams mayeffectively reduce interference between different reference signals,thereby improving channel estimation precision and ensuring CSImeasurement precision.

Specially, the reference signal resource configuration may have, but notbeing limited to, the following characteristics:

Characteristic 1: Antenna port sets corresponding to two referencesignal resource configurations have at least one same antenna port.Specifically, using the reference signal resource configurationinformation in Table 4 as an example, reference signal configurationscorresponding to the reference signal configuration information maycorrespond to different antenna port sets. As shown in Table 6, everytwo adjacent antenna port sets in 4-antenna-port sets have two sameantenna ports, and every two adjacent antenna port sets in8-antenna-port sets have four same antenna ports. On the one hand, thesystem can support more antenna ports. On the other hand, every tworeference signal configurations configured by the user equipment have atleast one same antenna port, so as to overcome a coverage gap betweenantenna ports and overcome an edge effect.

Characteristic 2: The reference signal sequence information is aninitial value or cyclic shift value of a reference signal sequence, ordifferent combinations of two base sequences. Specifically, thereference signal sequence information is different initial values orcyclic shift values of the reference signal sequence, or differentcombinations of two base sequences, as described above.

Characteristic 3: A different antenna port corresponding to eachreference signal resource configuration uses a different resourcereference signal configuration or a different reference signal sequence,as described above.

Specifically, for a different sounding signal type in step S501, theuser equipment determines the reference signal resource configurationindex according to the sounding signal set in the following specificimplementation manners.

Type 1: The sounding signal is a cell-specific reference signal (CRS) ora channel state information reference signal (CSI RS), and the referencesignal resource configuration index includes an RI₁ and/or a PMI₁.Specifically, the determining, by the user equipment, the RI₁ and/or thePMI₁ according to the CRS or the CSI RS includes: obtaining, by the userequipment, a channel estimation value according to the CRS or the CSIRS; and obtaining, by the user equipment, the channel estimation value,and selecting a first precoding matrix from a first codebook accordingto a preset criterion, where the first precoding matrix corresponds tothe RI₁ and/or the PMI₁.

The channel estimation may be implemented according to the prior art,for example, by using the least square (LS) method or the minimum meansquared error (MMSE) method.

The preset criterion may be a criterion such as capacity maximization ormutual information maximization or throughput maximization, which is notlimited in the present disclosure.

The first codebook is a precoding matrix set, in which each firstprecoding matrix is referred to as a codeword, and each codeword may beindicated by the RI₁ and/or the PMI₁.

Optionally, in an embodiment, the user equipment determines that aprecoding matrix included in the first codebook used by the firstprecoding matrix is a precoding matrix in a 2-antenna codebook, a4-antenna codebook, or an 8-antenna codebook in the LTE R10 system, oris a precoding matrix in a 2-antenna codebook, a 4-antenna codebook, oran 8-antenna codebook in an LTE R12 system.

In this embodiment of the present disclosure, optionally, as anembodiment, a precoding matrix included in the first codebook is adiscrete Fourier transform (DFT) matrix, a Hadamard matrix, aHouseholder matrix, a kronecker product of two DFT matrices, a kroneckerproduct of a DFT matrix and a Hadamard matrix, or a kronecker product ofa DFT matrix and a Householder matrix.

It should be pointed out that the precoding matrix in the first codebookmay be pre-stored on a user equipment side or on a base station side, ormay be calculated according to a structure of the precoding matrix, forexample, calculated according to a relationship between the firstprecoding matrix indicator and the precoding matrix, which, however, isnot limited in the present disclosure.

Selecting a precoding matrix according to a channel estimation by usinga preset criterion is the prior art, and is not further describedherein.

A correspondence between the RI₁ and/or the PMI₁ included in thereference signal resource configuration index and the reference signalresource configuration information may be predefined or may be notifiedby the base station to the user equipment by using higher layersignaling such as RRC signaling or DCI, which is specifically shown inTable 1 or Table 2.

The user equipment may obtain the corresponding reference signalresource configuration according to the correspondence and according tothe determined RI₁ and/or PMI₁ included in the reference signal resourceconfiguration index.

Further, the cell-specific reference signal (CRS) or the channel stateinformation reference signal (CSI RS) is specified by a specificreference signal resource configuration in the reference signal resourceconfiguration set information. For example, the CRS or the CSI RS isalways specified by using the first reference signal resourceconfiguration in the reference signal resource configuration setinformation.

Type 2: The sounding signal is a synchronization signal, and thereference signal resource configuration index is a resource identifiercarried in the synchronization signal or associated with a resourcelocation of the synchronization signal, where the resource identifiercarried in the synchronization signal or associated with the resourcelocation of the synchronization signal indicates a reference signalresource configuration in the reference signal resource configurationset information. Optionally, a different resource identifier carried inthe synchronization signal is denoted by a different synchronizationsignal sequence. Specifically, the resource identifier may be denoted bythe different synchronization signal sequence. For example, as mentionedabove, the synchronization signal sequence is a ZC sequence, andtherefore, a different resource identifier may correspond to a differentroot index value or a different cyclic shift value of the ZC sequence.For example, as mentioned above, the synchronization signal sequence isan m sequence or a Gold sequence or a combination thereof, andtherefore, a different resource identifier may correspond to a differentm sequence or Gold sequence, or a combination thereof, or a differentinitial value thereof, or a different cyclic shift value thereof.

The user equipment may directly determine, by detecting and determininga synchronization channel whose channel condition is favorable to theuser equipment, the reference signal resource configuration indexcorresponding to the sounding signal according to the synchronizationsignal or the resource identifier of the synchronization signal.Implementing time or frequency synchronization by using the structure ofthe synchronization signal and the corresponding synchronization signalsequence is the prior art, and is not described herein. In addition,selecting a synchronization signal whose channel condition is favorableto the user equipment may be implemented based on receive power, and isnot limited herein.

Type 3: The sounding signal is a broadcast channel. The reference signalresource configuration index is a resource identifier carried in thebroadcast channel or associated with a resource location of thebroadcast channel, where the resource identifier carried in thebroadcast channel or associated with the resource location of thebroadcast channel indicates a reference signal resource configuration inthe reference signal resource configuration set information.

Optionally, the resource identifier carried in the broadcast channel maybe carried in a broadcast message of a different resource element set,where a broadcast message of a different resource element set carries adifferent resource identifier. By means of detection and decoding toobtain a corresponding broadcast message, the user equipment can obtainthe corresponding resource identifier.

Optionally, the resource identifier carried in the broadcast channel isdenoted by a different cyclic redundancy check mask. By means ofdetection and decoding, the user equipment obtains the correspondingbroadcast channel, and then performs a hypothesis test on the used CRCmask to obtain the corresponding CRC mask, so as to obtain thecorresponding resource identifier. In addition, in the foregoing twoimplementations, the user equipment obtains, by detecting a broadcastchannel whose channel condition is favorable to the user equipment, aresource identifier whose channel condition is favorable to the userequipment.

Receiving the broadcast channel by using the structure of the broadcastchannel and the corresponding CRC is the prior aft, and is not describedherein. In addition, selecting a broadcast channel whose channelcondition is favorable to the user equipment may be implemented based onreceive power, and is not limited herein.

Optionally, a correspondence between the reference signal resourceconfiguration index and the indicated reference signal resourceconfiguration is predefined or is notified to the user equipment byusing higher layer signaling or downlink control information (DCI).

S503. The user equipment receives a reference signal set sent by thebase station, where the reference signal set corresponds to thereference signal resource configuration indicated by the referencesignal resource configuration index.

Specifically, the user equipment may receive only the reference signalset corresponding to the reference signal resource configurationindicated by the reference signal resource configuration index.

S504. The user equipment determines channel state information accordingto the reference signal set.

Specifically, the channel state information may include a CQI, a PMI, oran RI. The determining, by the user equipment, channel state informationCSI according to the reference signal set may include: obtaining, by theuser equipment, a channel estimation value according to the referencesignal set; and determining, by the user equipment, the CSI based on apreset criterion and according to the obtained channel estimation value.

Further, a specific implementation manner of determining, by the userequipment, channel state information according to the reference signalset may be: determining a PMI₂ according to the reference signal set,where the PMI₂ corresponds to a precoding matrix selected from a secondcodebook, the second codebook is determined according to the referencesignal resource configuration index, and the channel state informationincludes the PMI₂.

Specifically, the second codebook may be determined according to thereference signal resource configuration index. For example, differentcodebooks may be determined according to a correspondence between areference signal resource configuration index and a codebook, where thecorrespondence is shown in Table 3, in which C_(N,i) may be the i^(th)codebook of N antenna ports, where N=₄ or 8.

Using a 4-antenna codebook as an example, a precoding matrix in C_(4,0)may be a matrix in a 4-antenna codebook in an LTE system such as an R8or R11 system, and a precoding matrix in C_(4,i) may be shown by formula(22), where matrices W₀ and W_(i) may be a matrix in C_(4,0) and amatrix in C_(4,i) respectively, and θ,φ are phases. For example,

${\theta = \frac{\pi}{64}},\frac{\pi}{32},{\frac{\pi}{16}\mspace{14mu}\ldots}\mspace{11mu},{\varphi = \pi},\frac{\pi}{2},\frac{\pi}{4},\ldots\mspace{11mu},.$

Optionally, in an embodiment, the precoding matrix included in thesecond codebook is a discrete Fourier transform DFT matrix, a Hadamardmatrix, a Householder matrix, a kronecker product of two DFT matrices, akronecker product of a DFT matrix and a Hadamard matrix, or a kroneckerproduct of a DFT matrix and a Householder matrix.

In addition, the channel estimation may be implemented according to theprior art, for example, by using the least square method or the minimummean squared error method. The preset criterion may be a criterion suchas capacity maximization or mutual information maximization orthroughput maximization, which is not limited in the present disclosure.Selecting a precoding matrix according to a channel estimation by usinga preset criterion is the prior art, and is not further describedherein.

It should be pointed out that the precoding matrix in the secondcodebook may be pre-stored on the user equipment side or on the basestation side, or may be calculated according to the structure of theprecoding matrix, for example, calculated according to a relationshipbetween the second precoding matrix indicator and the precoding matrix,which, however, is not limited in the present disclosure.

S505. The user equipment sends the reference signal resourceconfiguration index and the channel state information to the basestation.

Optionally, the user equipment may send the reference signal resourceconfiguration index and the channel state information to the basestation separately on a same subframe or on different subframes.

Further, optionally, a period of sending the reference signal resourceconfiguration index is longer than a period of sending the channel stateinformation. The reference signal resource configuration index isactually used to indicate a CSI measurement reference signal, thesounding signal generally has stronger spatial correlation, timecorrelation, or frequency correlation than the antenna portcorresponding to the signal set, and a channel state changes relativelyslowly. Therefore, a time interval or span of sending the referencesignal resource configuration index may be longer, so as to furtherreduce time-frequency resource overheads occupied for sending of thesounding signal and reduce complexity of implementation by the UE.

In this embodiment of the present disclosure, a base station sends asounding signal set to user equipment, and the user equipment determinesa locally appropriate reference signal resource configuration indexaccording to the sounding signal set, where the reference signalresource configuration index is used to indicate a reference signalresource configuration in reference signal resource configuration setinformation. When the base station sends a reference signal set to theoutside, the user equipment obtains only a reference signal setcorresponding to the reference signal resource configuration indicatedby the reference signal resource configuration index, and thendetermines channel state information according to the reference signalset and reports the channel state information to the base station. Thiscan effectively save time-frequency resource overheads, and effectivelyreduce complexity of CSI measurement performed by the user equipment orimprove CSI feedback precision.

FIG. 9 is a schematic flowchart of another method for reporting channelstate information according to an embodiment of the present disclosure,where the method may include.

S601. A base station sends reference signal resource configuration setinformation to user equipment.

Specifically, the base station may notify the user equipment of thereference signal resource configuration set information by using higherlayer signaling such as RRC signaling or DCI.

The reference signal resource configuration set information may also bepredefined and known by both the user equipment and the base station.

The reference signal resource configuration set information includes atleast two reference signal resource configurations. Referring to Table4, Table 4 is an expression form of the reference signal resourceconfiguration set information. As shown in the table, there are eightdifferent reference signal resource configurations in the table. Areference signal resource configuration may include at least antennaport information and reference signal configuration information, wherethe reference signal configuration information is used to indicate aresource element used for sending a reference signal on an antenna port,and the antenna port information is a quantity of antenna portscorresponding to one of the reference signal configurations.

Optionally, the reference signal resource configuration set informationmay further include reference signal sequence information. For example,as shown in Table 5, the reference signal resource configuration indexes0, 1, 2, and 3 support four antenna ports, and use a same referencesignal configuration 0. That is, they occupy a same resource element butdifferent reference signal sequences 0, 1, 2, and 3. Antennascorresponding to the different reference signal sequences 0, 1, 2, and 3may be implemented by using different beams, and the different beams maybe orthogonal to each other. On the one hand, using the same resourceelement can avoid occupying too many time-frequency resources, therebyeffectively saving overheads. On the other hand, sending the differentreference signal sequences 0, 1, 2, and 3 by the different beams mayeffectively reduce interference between different reference signals,thereby improving channel estimation precision and ensuring CSImeasurement precision.

Specially, the reference signal resource configuration may have, but notbeing limited to, the following characteristics.

Characteristic 1: Antenna port sets corresponding to two referencesignal resource configurations have at least one same antenna port.Specifically, using the reference signal resource configurationinformation in Table 4 as an example, reference signal configurationscorresponding to the reference signal configuration information maycorrespond to different antenna port sets. As shown in Table 6, everytwo adjacent antenna port sets in 4-antenna-port sets have two sameantenna ports, and every two adjacent antenna port sets in8-antenna-port sets have four same antenna ports. On the one hand, thesystem can support more antenna ports. On the other hand, every tworeference signal configurations configured by the user equipment have atleast one same antenna port, so as to overcome a coverage gap betweenantenna ports and overcome an edge effect.

Characteristic 2: The reference signal sequence information is aninitial value or cyclic shift value of a reference signal sequence, ordifferent combinations of two base sequences. Specifically, thereference signal sequence information is different initial values orcyclic shift values of the reference signal sequence, or differentcombinations of two base sequences, as described above.

Characteristic 3: A different antenna port corresponding to eachreference signal resource configuration uses a different resourcereference signal configuration or a different reference signal sequence,as described above.

S602. The base station sends a sounding signal set to the userequipment.

The sounding signal set includes at least one sounding signal. It shouldbe pointed out that.

In a first optional implementation manner, the sounding signal is acell-specific reference signal or a channel state information referencesignal. The CRS may support a cell-specific antenna port configuration,and is received by all user equipments in this cell. For example, theCRS may be a reference signal corresponding to an antenna port 0, 1, 2,or 3 in an LTE R8 system. The CSI RS supports signal transmission on acell-specific antenna port and signal receiving on a user equipmentspecific antenna port. For example, the CSI RS may be a reference signalcorresponding to an antenna port 15, 16, . . . , or 22 in an LTE R10system. It should be pointed out that the CRS or the CSI RS is notlimited to a current LTE system.

In a second optional implementation manner, the sounding signal is asynchronization signal. The synchronization signal is used to implementtime and frequency synchronization. One of multiple known or optionalsynchronization signal sequences is mapped to a resource element set ofa synchronization signal. According to the known or optionalsynchronization signal sequence, the user equipment may implement timeand frequency synchronization by detecting the synchronization signal.

Specifically, the synchronization signal may be sent on at least oneresource element set separately. For example, using a frame structure inan LTE system as an example, the at least one resource element set maybe shown by formulas (1) and (2). The triplet (k, l, n_(s)) denotes alocation of a resource element used for the synchronization signal,where k, l, and n_(s) are respectively a subcarrier index, an OFDMsymbol index, and a timeslot index of the resource element; N_(SS)denotes a length of a synchronization signal sequence.

Specifically, in each resource element set, the synchronization signalsends a synchronization signal sequence. The synchronization signalsequence may be a Zadoff-Chu (ZC) sequence. Using N_(SS)=62 as anexample, the synchronization signal sequence is a ZC sequence shown byformula (3), or a cyclic shift of the ZC sequence shown by formula (4).The parameter u is a root index of the ZC sequence, and its value maybe, for example, 25, 29, or 34; the parameter v is a cyclic shift value,and its value may be, for example, a positive integer such as 3 or 6.

Optionally, the synchronization signal sequence may also be an msequence or a Gold sequence or a combination thereof, and is not furtherenumerated herein.

Specifically, the synchronization signal sequence may be separatelymapped to different resource element sets. Using the ZC sequence whoselength is 62 as an example, 62 elements in the sequence may be mapped to62 resource element locations respectively. For example, a sequenceelement in an RE location (k, l, n_(s)) in the resource element setS_(i) ^(SS) is formula (5) or formula (6), where u_(i) and v_(i) arerespectively a root index value and a cyclic shift value of a ZCsequence used for the synchronization signal on the resource element setS_(i) ^(SS). A synchronization signal on a different resource elementset S_(i) ^(SS) may use a different root index value or a differentcyclic shift value or a combination thereof. It should be pointed outthat a different u_(i) or v_(i) or a combination (u_(i),v_(i)) thereofmay correspond to a different piece of information, so that thesynchronization signal sent on the different resource element setscarries different information.

In a third optional implementation manner, the sounding signal is abroadcast channel. The broadcast channel is used to send a broadcastmessage. The broadcast message may include, for example, a systembandwidth, a system frame number, physical channel configurationindication information, or a combination thereof.

Specifically, the broadcast channel may be sent on at least one resourceelement set separately. For example, using a frame structure in an LTEsystem as an example, the at least one resource element set may be shownby formulas (7) and (8) or formulas (9) and (10).

The quadruplet (k, l, n_(s), n_(f)) denotes a location of a resourceelement used for the broadcast channel, where k, l, n_(s), and n_(f) arerespectively a subcarrier index, an OFDM symbol index, a timeslot index,and a system frame number of the resource element; j₀≠j₁, and valueranges of all parameters j, j₀, and j₁ are 0 to 4N−1. The positiveinteger N in formulas (7) to (10) may be 1 or a positive integer greaterthan 1.

Specifically, a broadcast channel sent by each resource element groupmay be mapped to a corresponding resource element set after undergoingchannel coding (by using a convolutional code or a Turbo code) andmodulation. In addition, before channel coding, a cyclic redundancycheck (CRC) code may be appended to the broadcast message.

Optionally, the broadcast channels in the different resource elementsets may further carry additional information separately in addition tothe system broadcast information. Optionally, an implementation mannermay be:

Manner 1: The additional information and the broadcast information forma broadcast message, and undergo processing such as channel coding.

Manner 2: The additional information is denoted by a different CRC mask(Mask). Specifically, a CRC check bit corresponding to the broadcastmessage carried in the broadcast channel is p_(n), n=0, 1, 2, . . . ,N_(CRC)−1, and a CRC mask corresponding to the indication information isx_(n), n=0, 1, 2, . . . , N_(CRC)−1. Therefore, after CRC maskscrambling, bit sequences shown by formulas (11) to (15) are generated.

It should be specially noted that the foregoing three implementationmanners merely show three specific sounding signal types proposed inthis embodiment of the present disclosure. However, type of the soundingsignal is not limited thereto, and is not enumerated exhaustivelyherein.

S603. The user equipment determines a reference signal resourceconfiguration index according to the sounding signal set.

Specifically, the user equipment determines the reference signalresource configuration index according to the received sounding signalset.

It should be pointed out that the reference signal resourceconfiguration index is used to indicate a reference signal resourceconfiguration in the reference signal resource configuration setinformation. Generally, each reference signal corresponds to one antennaport. By means of a least square (LS) method, a minimum mean squarederror (MMSE) method, or the like, a channel estimation on acorresponding antenna port may be obtained according to a resourceelement location occupied by each reference signal in a resource grid ofthe corresponding antenna port.

Specifically, the reference signal resource configuration may includeinformation such as a supported quantity of antenna ports, a referencesignal sending period and an offset in the sending period, an RElocation occupied by a reference signal, or a reference signal sequence.The RE location occupied by the reference signal or a time-frequencypattern of the reference signal is generally referred to as a referencesignal configuration. Using 8 antenna ports as an example, RE locationscorresponding to the 8 antenna ports in frame structures FS1 and FS areshown in FIG. 2a and FIG. 2b respectively. Using 16 antenna ports as anexample, RE locations corresponding to the 16 antenna ports in the framestructures FS1 and FS are shown in FIG. 3a and FIG. 3b respectively.Using FIG. 3a as an example, RE locations denoted by digits 0, 1, . . ., 7 in the figure are locations occupied by reference signals.

Specifically, the reference signal sends a reference signal sequence onan occupied resource element set. Optionally, the reference signalsequence may be a ZC sequence or an m sequence, or may be obtainedaccording to a combination of two base sequences or according to apseudo random sequence, or the like. Optionally, the reference signalsequence may be obtained by means of cyclic shift according to a rootsequence, or the reference signal sequence may be obtained according toa combination of two base sequences.

Type 1: The sounding signal is a CRS or a channel state informationreference signal CSI RS, and the reference signal resource configurationindex includes an RI₁ and/or a PMI₁. Specifically, the determining, bythe user equipment, the RI₁ and/or the PMI₁ according to the CRS or theCSI RS includes: obtaining, by the user equipment, a channel estimationvalue according to the CRS or the CSI RS; and obtaining, by the userequipment, the channel estimation value, and selecting a first precodingmatrix from a first codebook according to a preset criterion, where thefirst precoding matrix corresponds to the RI₁ and/or the PMI₁.

The channel estimation may be implemented according to the prior are,for example, by using the least square (LS) method or the minimum meansquared error (MMSE) method.

The preset criterion may be a criterion such as capacity maximization ormutual information maximization or throughput maximization, which is notlimited in the present disclosure.

The first codebook is a precoding matrix set, in which each firstprecoding matrix is referred to as a codeword, and each codeword may beindicated by the RI₁ and/or the PMI₁.

Optionally, in an embodiment, the user equipment determines that aprecoding matrix included in the first codebook used by the firstprecoding matrix is a precoding matrix in a 2-antenna codebook, a4-antenna codebook, or an 8-antenna codebook in the LTE R10 system, oris a precoding matrix in a 2-antenna codebook, a 4-antenna codebook, oran 8-antenna codebook in an LTE R12 system.

In this embodiment of the present disclosure, optionally, as anembodiment, a precoding matrix included in the first codebook is adiscrete Fourier transform (DFT) matrix, a Hadamard matrix, aHouseholder matrix, a kronecker product of two DFT matrices, a kroneckerproduct of a DFT matrix and a Hadamard matrix, or a kronecker product ofa DFT matrix and a Householder matrix.

It should be pointed out that the precoding matrix in the first codebookmay be pre-stored on a user equipment side or on a base station side, ormay be calculated according to a structure of the precoding matrix, forexample, calculated according to a relationship between the firstprecoding matrix indicator and the precoding matrix, which, however, isnot limited in the present disclosure.

Selecting a precoding matrix according to a channel estimation by usinga preset criterion is the prior aft, and is not further describedherein.

A correspondence between the RI₁ and/or the PMI₁ included in thereference signal resource configuration index and the reference signalresource configuration information may be predefined or may be notifiedby the base station to the user equipment by using higher layersignaling such as RRC signaling or DCI, which is specifically shown inTable 1 or Table 2.

The user equipment may obtain the corresponding reference signalresource configuration according to the correspondence and according tothe determined RI₁ and/or PMI₁ included in the reference signal resourceconfiguration index.

Further, the CRS or the CSI RS is specified by a specific referencesignal resource configuration in the reference signal resourceconfiguration set information. For example, the CRS or the CSI RS isalways specified by using the first reference signal resourceconfiguration in the reference signal resource configuration setinformation.

Type 2: The sounding signal is a synchronization signal, and thereference signal resource configuration index is a resource identifiercarried in the synchronization signal or associated with a resourcelocation of the synchronization signal, where the resource identifiercarried in the synchronization signal or associated with the resourcelocation of the synchronization signal indicates a reference signalresource configuration in the reference signal resource configurationset information. Optionally, a different resource identifier carried inthe synchronization signal is denoted by a different synchronizationsignal sequence. Specifically, the resource identifier may be denoted bythe different synchronization signal sequence. For example, as mentionedabove, the synchronization signal sequence is a ZC sequence, andtherefore, a different resource identifier may correspond to a differentroot index value or a different cyclic shift value of the ZC sequence.For example, as mentioned above, the synchronization signal sequence isan m sequence or a Gold sequence or a combination thereof, andtherefore, a different resource identifier may correspond to a differentm sequence or Gold sequence, or a combination thereof, or a differentinitial value thereof, or a different cyclic shift value thereof.

The user equipment may directly determine, by detecting and determininga synchronization channel whose channel condition is favorable to theuser equipment, the reference signal resource configuration indexcorresponding to the sounding signal according to the synchronizationsignal or the resource identifier of the synchronization signal.Implementing time or frequency synchronization by using the structure ofthe synchronization signal and the corresponding synchronization signalsequence is the prior art, and is not described herein. In addition,selecting a synchronization signal whose channel condition is favorableto the user equipment may be implemented based on receive power, and isnot limited herein.

Type 3: The sounding signal is a broadcast channel. The reference signalresource configuration index is a resource identifier carried in thebroadcast channel or associated with a resource location of thebroadcast channel, where the resource identifier carried in thebroadcast channel or associated with the resource location of thebroadcast channel indicates a reference signal resource configuration inthe reference signal resource configuration set information.

Optionally, the resource identifier carried in the broadcast channel maybe carried in a broadcast message of a different resource element set,where a broadcast message of a different resource element set carries adifferent resource identifier. By means of detection and decoding toobtain a corresponding broadcast message, the user equipment can obtainthe corresponding resource identifier.

Optionally, the resource identifier carried in the broadcast channel isdenoted by a different cyclic redundancy check mask. By means ofdetection and decoding, the user equipment obtains the correspondingbroadcast channel, and then performs a hypothesis test on the used CRCmask to obtain the corresponding CRC mask, so as to obtain thecorresponding resource identifier. In addition, in the foregoing twoimplementations, the user equipment obtains, by detecting a broadcastchannel whose channel condition is favorable to the user equipment, aresource identifier whose channel condition is favorable to the userequipment.

Receiving the broadcast channel by using the structure of the broadcastchannel and the corresponding CRC is the prior aft, and is not describedherein. In addition, selecting a broadcast channel whose channelcondition is favorable to the user equipment may be implemented based onreceive power, and is not limited herein.

Optionally, a correspondence between the reference signal resourceconfiguration index and the indicated reference signal resourceconfiguration is predefined (Predefined) or is notified to the userequipment by using higher layer signaling or DCI.

S604. The base station sends at least two reference signal sets to theuser equipment.

The reference signal set has been elaborated earlier above, and is notdescribed herein. It should be pointed out that the user equipment mayreceive only a reference signal set corresponding to the referencesignal resource configuration indicated by the reference signal resourceconfiguration index.

S605. The user equipment determines channel state information accordingto the reference signal sets.

Specifically, the channel state information may include a CQI, a PMI, oran RI. The determining, by the user equipment, channel state informationCSI according to the reference signal set may include: obtaining, by theuser equipment, a channel estimation value according to the referencesignal set; and determining, by the user equipment, the CSI based on apreset criterion and according to the obtained channel estimation value.

Further, a specific implementation manner of determining, by the userequipment, channel state information according to the reference signalset may be: determining a PMI₂ according to the reference signal set,where the PMI₂ corresponds to a precoding matrix selected from a secondcodebook, the second codebook is determined according to the referencesignal resource configuration index, and the channel state informationincludes the PMI₂.

Specifically, the second codebook may be determined according to thereference signal resource configuration index. For example, differentcodebooks may be determined according to a correspondence between areference signal resource configuration index and a codebook, where thecorrespondence is shown in Table 3, in which C_(N,i) may be the i^(th)codebook of N antenna ports, where N=4 or 8. Using a 4-antenna codebookas an example, a precoding matrix in C_(4,0) may be a matrix in a4-antenna codebook in an LTE system such as an R8 or R11 system, and aprecoding matrix in C_(4,i) may be shown by formula (22).

Optionally, in an embodiment, the precoding matrix included in thesecond codebook is a DFT matrix, a Hadamard matrix, a Householdermatrix, a kronecker product of two DFT matrices, a kronecker product ofa DFT matrix and a Hadamard matrix, or a kronecker product of a DFTmatrix and a Householder matrix.

In addition, the channel estimation may be implemented according to theprior art, for example, by using the least square method or the minimummean squared error method. The preset criterion may be a criterion suchas capacity maximization or mutual information maximization orthroughput maximization, which is not limited in the present disclosure.Selecting a precoding matrix according to a channel estimation by usinga preset criterion is the prior art, and is not further describedherein.

It should be pointed out that the precoding matrix in the secondcodebook may be pre-stored on the user equipment side or on the basestation side, or may be calculated according to the structure of theprecoding matrix, for example, calculated according to a relationshipbetween the second precoding matrix indicator and the precoding matrix,which, however, is not limited in the present disclosure.

S606. The user equipment sends the reference signal resourceconfiguration index and the channel state information to the basestation.

Specifically, the user equipment sends the reference signal resourceconfiguration index and reports the channel state information to thebase station.

Optionally, the user equipment may send the reference signal resourceconfiguration index and the channel state information to the basestation separately on a same subframe or on different subframes.

Further, optionally, a period of sending the reference signal resourceconfiguration index is longer than a period of sending the channel stateinformation. The reference signal resource configuration index isactually used to indicate a CSI measurement reference signal, thesounding signal generally has stronger spatial correlation, timecorrelation, or frequency correlation than the antenna portcorresponding to the signal set, and a channel state changes relativelyslowly. Therefore, a time interval or span of sending the referencesignal resource configuration index may be longer, so as to furtherreduce time-frequency resource overheads occupied for sending of thesounding signal and reduce complexity of implementation by the UE.

In this embodiment of the present disclosure, a base station sends asounding signal set to user equipment, and the user equipment determinesa locally appropriate reference signal resource configuration indexaccording to the sounding signal set, where the reference signalresource configuration index is used to indicate a reference signalresource configuration in reference signal resource configuration setinformation. When the base station sends a reference signal set to theoutside, the user equipment obtains only a reference signal setcorresponding to the reference signal resource configuration indicatedby the reference signal resource configuration index, and thendetermines channel state information according to the reference signalset and reports the channel state information to the base station. Thiscan effectively save time-frequency resource overheads, and effectivelyreduce complexity of CSI measurement performed by the user equipment orimprove CSI feedback precision.

An embodiment of the present disclosure further proposes a computerstorage medium, and the computer storage medium stores a program. Whenbeing executed, the program includes some or all of the steps in themethod for reporting channel state information that is described withreference to FIG. 5 to FIG. 6 in the embodiments of the presentdisclosure.

In this embodiment of the present disclosure, a base station sends asounding signal set to user equipment, and the user equipment determinesa locally appropriate reference signal resource configuration indexaccording to the sounding signal set, where the reference signalresource configuration index is used to indicate a reference signalresource configuration in reference signal resource configuration setinformation. When the base station sends a reference signal set to theoutside, the user equipment obtains only a reference signal setcorresponding to the reference signal resource configuration indicatedby the reference signal resource configuration index, and thendetermines channel state information according to the reference signalset and reports the channel state information to the base station. Thiscan effectively save time-frequency resource overheads, and effectivelyreduce complexity of CSI measurement performed by the user equipment orimprove CSI feedback precision.

A person of ordinary skill in the art may understand that all or some ofthe processes of the methods in the embodiments may be implemented by acomputer program instructing relevant hardware. The program may bestored in a computer-readable storage medium. When the program runs, theprocesses of the methods in the embodiments are performed. The foregoingstorage medium may include: a magnetic disk, an optical disc, aread-only memory (ROM), a random access memory (RAM), or the like.

What is disclosed above is merely exemplary embodiments of the presentdisclosure, and certainly is not intended to limit the protection scopeof the present disclosure. Therefore, equivalent variations made inaccordance with the claims of the present disclosure shall fall withinthe scope of the present disclosure.

What is claimed is:
 1. A user equipment comprising: a processor; and anon-transitory computer readable storage medium storing a program forexecution by the processor, the program including instructions to:receive a sounding signal set sent by a base station, wherein thesounding signal set comprises at least one sounding signal; determine areference signal resource configuration index according to the soundingsignal set, wherein the reference signal resource configuration indexindicates a reference signal resource configuration in reference signalresource configuration set information; receive a reference signal setsent by the base station, wherein the reference signal set correspondsto the reference signal resource configuration indicated by thereference signal resource configuration index; determine channel stateinformation according to the reference signal set; and send, to the basestation, the reference signal resource configuration index and thechannel state information.
 2. The user equipment according to claim 1,wherein the program further comprises instructions to: receive thereference signal resource configuration set information sent by the basestation, wherein the reference signal resource configuration setinformation comprises at least two reference signal resourceconfigurations.
 3. The user equipment according to claim 1, wherein thesounding signal is a cell-specific reference signal (CRS) or a channelstate information reference signal (CSI RS), and wherein the referencesignal resource configuration index comprises at least one of a firstrank indicator (RI₁) and a first precoding matrix indicator (PMI₁). 4.The user equipment according to claim 1, wherein the sounding signal isa synchronization signal, wherein the reference signal resourceconfiguration index is a resource identifier carried in thesynchronization signal or associated with a resource location of thesynchronization signal, and wherein the resource identifier carried inthe synchronization signal or associated with the resource location ofthe synchronization signal indicates a reference signal resourceconfiguration in the reference signal resource configuration setinformation.
 5. The user equipment according to claim 1, wherein thesounding signal is a broadcast channel, wherein the reference signalresource configuration index is a resource identifier carried in thebroadcast channel or associated with a resource location of thebroadcast channel, and wherein the resource identifier carried in thebroadcast channel or associated with the resource location of thebroadcast channel indicates a reference signal resource configuration inthe reference signal resource configuration set information.
 6. The userequipment according to claim 1, wherein the reference signal resourceconfiguration comprises at least one of antenna port information andreference signal configuration information and reference signal sequenceinformation, wherein the reference signal configuration informationindicates a resource element used for sending a reference signal on anantenna port.
 7. The user equipment according to claim 6, whereinantenna port sets corresponding to two reference signal resourceconfigurations have at least one same antenna port.
 8. A base stationcomprising: a processor; and a non-transitory computer readable storagemedium storing a program for execution by the processor, the programincluding instructions to: send, to a user equipment, a sounding signalset, wherein the sounding signal set comprises at least one soundingsignal, causing the user equipment to determine a reference signalresource configuration index according to the sounding signal set,wherein the reference signal resource configuration index indicates areference signal resource configuration in reference signal resourceconfiguration set information for obtaining channel state information;send, to the user equipment, at least two reference signal sets, whereinthe at least two reference signal sets correspond to at least tworeference signal resource configurations in the reference signalresource configuration set information; and receive the reference signalresource configuration index and the channel state information that aresent by the user equipment.
 9. The base station according to claim 8,wherein the program further comprises instructions to send the referencesignal resource configuration set information to the user equipment,wherein the reference signal resource configuration set informationcomprises the at least two reference signal resource configurations. 10.The base station according to claim 8, wherein the sounding signal is acell-specific reference signal (CRS) or a channel state informationreference signal (CSI RS), and wherein the reference signal resourceconfiguration index comprises at least one of a first rank indicator(RI₁) and a first precoding matrix indicator (PMI₁).
 11. The basestation according to claim 8, wherein the sounding signal is asynchronization signal, wherein the reference signal resourceconfiguration index is a resource identifier carried in thesynchronization signal or associated with a resource location of thesynchronization signal, and wherein the resource identifier carried inthe synchronization signal or associated with the resource location ofthe synchronization signal indicates a reference signal resourceconfiguration in the reference signal resource configuration setinformation.
 12. The base station according to claim 8, wherein thesounding signal is a broadcast channel, wherein the reference signalresource configuration index is a resource identifier carried in thebroadcast channel or associated with a resource location of thebroadcast channel, and wherein the resource identifier carried in thebroadcast channel or associated with the resource location of thebroadcast channel indicates a reference signal resource configuration inthe reference signal resource configuration set information.
 13. Thebase station according to claim 8, wherein the reference signal resourceconfiguration set information comprises at least one of antenna portinformation and reference signal configuration information and referencesignal sequence information, and wherein the reference signalconfiguration information is used to indicate a resource element usedfor sending a reference signal on an antenna port.
 14. The base stationaccording to claim 13, wherein antenna port sets corresponding to the atleast two reference signal resource configurations have at least onesame antenna port.
 15. A method comprising: receiving, by a userequipment, a sounding signal set sent by a base station, wherein thesounding signal set comprises at least one sounding signal; determining,by the user equipment, a reference signal resource configuration indexaccording to the sounding signal set, wherein the reference signalresource configuration index indicates a reference signal resourceconfiguration in reference signal resource configuration setinformation; receiving, by the user equipment, a reference signal setsent by the base station, wherein the reference signal set correspondsto the reference signal resource configuration indicated by thereference signal resource configuration index; determining, by the userequipment, channel state information according to the reference signalset; and sending, by the user equipment to the base station, thereference signal resource configuration index and the channel stateinformation.
 16. The method according to claim 15, wherein the methodfurther comprises: receiving, by the user equipment, the referencesignal resource configuration set information sent by the base station,wherein the reference signal resource configuration set informationcomprises at least two reference signal resource configurations.
 17. Themethod according to claim 15, wherein the sounding signal is acell-specific reference signal (CRS) or a channel state informationreference signal (CSI RS), and wherein the reference signal resourceconfiguration index comprises at least one of a first rank indicator(RI₁) and a PMI₁.
 18. The method according to claim 15, wherein thesounding signal is a synchronization signal, wherein the referencesignal resource configuration index is a resource identifier carried inthe synchronization signal or associated with a resource location of thesynchronization signal, and wherein the resource identifier carried inthe synchronization signal or associated with the resource location ofthe synchronization signal indicates a reference signal resourceconfiguration in the reference signal resource configuration setinformation.
 19. The method according to claim 15, wherein the soundingsignal is a broadcast channel, wherein the reference signal resourceconfiguration index is a resource identifier carried in the broadcastchannel or associated with a resource location of the broadcast channel,and wherein the resource identifier carried in the broadcast channel orassociated with the resource location of the broadcast channel indicatesa reference signal resource configuration in the reference signalresource configuration set information.
 20. The method according toclaim 15, wherein the reference signal resource configuration comprisesat least one of antenna port information and reference signalconfiguration information and reference signal sequence information, andwherein the reference signal configuration information is used toindicate a resource element used for sending a reference signal on anantenna port.